<!doctype html public '-//W3C//DTD HTML Experimental 19960712//EN'>
<!-- $Id: REC-CSS1-961217.html,v 1.8 1998/04/07 21:08:44 fillault Exp $ -->
<HTML>
<HEAD>
  <STYLE TYPE="text/css">
  <!--
  BODY {
    margin-left: 2%;
    margin-right: 2%;
    color: black;
    font-family: sans-serif;
    background: #def url(recbg.jpg);
  }

  A:link {
    color: red
  }

  A:visited {
    color: blue
  }

  DIV.spec {
    margin-left: 13%;
  }

  DIV.spec H2, DIV.spec H3 {
    margin-left: -13%;
  }

  H1 {
    clear: left;
    margin-top: 2em;
    text-align: center;
  }

  PRE {
    font-family: monospace;
    /* font-size: 90%; */
  }

  IMG {
    border: 0;
  }

  -->
  </STYLE>
  <TITLE>Cascading Style Sheets, level 1</TITLE>
</HEAD>
<BODY BACKGROUND="http://www.w3.org/pub/WWW/TR/recbg.jpg">
<H3 align=right>
  <A HREF="http://www.w3.org/">
  <IMG border=0 align=left alt="W3C" src="http://www.w3.org/pub/WWW/Icons/WWW/w3c_home"></A>
  REC-CSS1-961217
</H3>
<P>
<BR clear=left>
<!-- END HEADER -->
<H1 align=center>
  Cascading Style Sheets, level 1
</H1>
<H3 align=center>
  W3C Recommendation 17 Dec 1996
</H3>
<DL>
  <DT>
    This is:
  <DD>
    <A HREF="http://www.w3.org/pub/WWW/TR/REC-CSS1">http://www.w3.org/pub/WWW/TR/REC-CSS1</A>
  <DT>
    Authors:
  <DD>
    <A HREF="http://www.w3.org/People/howcome/">H&aring;kon Wium Lie</A>
    (howcome@w3.org)<BR>
    <A HREF="http://www.w3.org/People/Bos/">Bert Bos</A> (bert@w3.org)
</DL>
<P>
  <HR>
<H3>
  Status of this document
</H3>
<P>
This document is a W3C Recommendation. It has been reviewed by
<A HREF="http://www.w3.org/">W3C</A> (http://www.w3.org/) Members and general
consensus that the specification is appropriate for use has been reached.
It is a stable document and may be used as reference material or cited as
a normative reference from another document. W3C promotes widespread deployment
of this Recommendation.
<P>
A list of current W3C Recommendations and other technical documents can be
found at <A href="http://www.w3.org/pub/WWW/TR/">
http://www.w3.org/pub/WWW/TR/</A>. 
  <HR>
<DIV CLASS=spec>
  <H2>
    <A name="abstract">Abstract</A>
  </H2>
  <P>
  This document specifies level 1 of the Cascading Style Sheet mechanism (CSS1).
  CSS1 is a simple style sheet mechanism that allows authors and readers to
  attach style (e.g. fonts, colors and spacing) to HTML documents. The CSS1
  language is human readable and writable, and expresses style in common desktop
  publishing terminology.
  <P>
  One of the fundamental features of CSS is that style sheets cascade; authors
  can attach a preferred style sheet, while the reader may have a personal
  style sheet to adjust for human or technological handicaps. The rules for
  resolving conflicts between different style sheets are defined in this
  specification.
  <P>
  This Recommendation results from W3C activities in the area of
  <A HREF="http://www.w3.org/pub/WWW/Style/Activity">Style Sheets</A>. For
  background information on style sheets, see <A HREF="#ref1">[1]</A>.
  <H2>
    <A name="table-of-contents">Table of contents</A>
  </H2>
  <P>
  <A HREF="#abstract">Abstract</A><BR>
  <A HREF="#terminology">Terminology</A><BR>
  <BR>
  <A HREF="#basic-concepts">1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Basic concepts</A><BR>
  <A HREF="#containment-in-html">1.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Containment in HTML</A><BR>
  <A HREF="#grouping">1.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Grouping</A><BR>
  <A HREF="#inheritance">1.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Inheritance</A><BR>
  <A HREF="#class-as-selector">1.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Class as selector</A><BR>
  <A HREF="#id-as-selector">1.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ID as selector</A><BR>
  <A HREF="#contextual-selectors">1.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Contextual selectors</A><BR>
  <A HREF="#comments">1.7
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Comments</A><BR>
  <A HREF="#pseudo-classes-and-pseudo-elements">2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pseudo-classes and
  pseudo-elements</A><BR>
  <A HREF="#anchor-pseudo-classes">2.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Anchor pseudo-classes</A><BR>
  <A HREF="#typographical-pseudo-elements">2.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Typographical
  pseudo-elements</A><BR>
  <A HREF="#the-first-line-pseudo-element">2.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The 'first-line'
  pseudo-element</A><BR>
  <A HREF="#the-first-letter-pseudo-element">2.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The 'first-letter'
  pseudo-element</A><BR>
  <A HREF="#pseudo-elements-in-selectors">2.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Pseudo-elements in
  selectors</A><BR>
  <A HREF="#multiple-pseudo-elements">2.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Multiple
  pseudo-elements</A><BR>
  <A HREF="#the-cascade">3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The cascade</A><BR>
  <A HREF="#important">3.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'important'</A><BR>
  <A HREF="#cascading-order">3.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Cascading order</A><BR>
  <A HREF="#formatting-model">4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Formatting model</A><BR>
  <A HREF="#block-level-elements">4.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Block-level elements</A><BR>
  <A HREF="#vertical-formatting">4.1.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Vertical formatting</A><BR>
  <A HREF="#horizontal-formatting">4.1.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Horizontal formatting</A><BR>
  <A HREF="#list-item-elements">4.1.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;List-item elements</A><BR>
  <A HREF="#floating-elements">4.1.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Floating elements</A><BR>
  <A HREF="#inline-elements">4.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Inline elements</A><BR>
  <A HREF="#replaced-elements">4.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Replaced elements</A><BR>
  <A HREF="#the-height-of-lines">4.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The height of lines</A><BR>
  <A HREF="#the-canvas">4.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;The canvas</A><BR>
  <A HREF="#br-elements">4.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'BR' elements</A><BR>
  <A HREF="#css1-properties">5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CSS1 properties</A><BR>
  <A HREF="#notation-for-property-values">5.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Notation for property
  values</A><BR>
  <A HREF="#font-properties">5.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Font properties</A><BR>
  <A HREF="#font-matching">5.2.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Font matching</A><BR>
  <A HREF="#font-family">5.2.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'font-family'</A><BR>
  <A HREF="#font-style">5.2.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'font-style'</A><BR>
  <A HREF="#font-variant">5.2.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'font-variant'</A><BR>
  <A HREF="#font-weight">5.2.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'font-weight'</A><BR>
  <A HREF="#font-size">5.2.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'font-size'</A><BR>
  <A HREF="#font">5.2.7
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'font'</A><BR>
  <A HREF="#color-and-background-properties">5.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Color and background
  properties</A><BR>
  <A HREF="#color">5.3.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'color'</A><BR>
  <A HREF="#background-color">5.3.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'background-color'</A><BR>
  <A HREF="#background-image">5.3.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'background-image'</A><BR>
  <A HREF="#background-repeat">5.3.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'background-repeat'</A><BR>
  <A HREF="#background-attachment">5.3.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'background-attachment'</A><BR>
  <A HREF="#background-position">5.3.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'background-position'</A><BR>
  <A HREF="#background">5.3.7
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'background'</A><BR>
  <A HREF="#text-properties">5.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Text properties</A><BR>
  <A HREF="#word-spacing">5.4.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'word-spacing'</A><BR>
  <A HREF="#letter-spacing">5.4.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'letter-spacing'</A><BR>
  <A HREF="#text-decoration">5.4.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'text-decoration'</A><BR>
  <A HREF="#vertical-align">5.4.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'vertical-align'</A><BR>
  <A HREF="#text-transform">5.4.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'text-transform'</A><BR>
  <A HREF="#text-align">5.4.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'text-align'</A><BR>
  <A HREF="#text-indent">5.4.7
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'text-indent'</A><BR>
  <A HREF="#line-height">5.4.8
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'line-height'</A><BR>
  <A HREF="#box-properties">5.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Box properties</A><BR>
  <A HREF="#margin-top">5.5.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'margin-top'</A><BR>
  <A HREF="#margin-right">5.5.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'margin-right'</A><BR>
  <A HREF="#margin-bottom">5.5.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'margin-bottom'</A><BR>
  <A HREF="#margin-left">5.5.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'margin-left'</A><BR>
  <A HREF="#margin">5.5.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'margin'</A><BR>
  <A HREF="#padding-top">5.5.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'padding-top'</A><BR>
  <A HREF="#padding-right">5.5.7
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'padding-right'</A><BR>
  <A HREF="#padding-bottom">5.5.8
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'padding-bottom'</A><BR>
  <A HREF="#padding-left">5.5.9
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'padding-left'</A><BR>
  <A HREF="#padding">5.5.10
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'padding'</A><BR>
  <A HREF="#border-top-width">5.5.11
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-top-width'</A><BR>
  <A HREF="#border-right-width">5.5.12
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-right-width'</A><BR>
  <A HREF="#border-bottom-width">5.5.13
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-bottom-width'</A><BR>
  <A HREF="#border-left-width">5.5.14
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-left-width'</A><BR>
  <A HREF="#border-width">5.5.15
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-width'</A><BR>
  <A HREF="#border-color">5.5.16
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-color'</A><BR>
  <A HREF="#border-style">5.5.17
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-style'</A><BR>
  <A HREF="#border-top">5.5.18
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-top'</A><BR>
  <A HREF="#border-right">5.5.19
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-right'</A><BR>
  <A HREF="#border-bottom">5.5.20
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-bottom'</A><BR>
  <A HREF="#border-left">5.5.21
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border-left'</A><BR>
  <A HREF="#border">5.5.22
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'border'</A><BR>
  <A HREF="#width">5.5.23
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'width'</A><BR>
  <A HREF="#height">5.5.24
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'height'</A><BR>
  <A HREF="#float">5.5.25
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'float'</A><BR>
  <A HREF="#clear">5.5.26
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'clear'</A><BR>
  <A HREF="#classification-properties">5.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Classification
  properties</A><BR>
  <A HREF="#display">5.6.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'display'</A><BR>
  <A HREF="#white-space">5.6.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'white-space'</A><BR>
  <A HREF="#list-style-type">5.6.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'list-style-type'</A><BR>
  <A HREF="#list-style-image">5.6.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'list-style-image'</A><BR>
  <A HREF="#list-style-position">5.6.5
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'list-style-position'</A><BR>
  <A HREF="#list-style">5.6.6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;'list-style'</A><BR>
  <A HREF="#units">6
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Units</A><BR>
  <A HREF="#length-units">6.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Length units</A><BR>
  <A HREF="#percentage-units">6.2
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Percentage units</A><BR>
  <A HREF="#color-units">6.3
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Color units</A><BR>
  <A HREF="#url">6.4
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;URL</A><BR>
  <A HREF="#css1-conformance">7
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;CSS1 conformance</A><BR>
  <A HREF="#forward-compatible-parsing">7.1
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Forward-compatible
  parsing</A><BR>
  <A HREF="#references">8
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;References</A><BR>
  <A HREF="#acknowledgments">9
  &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Acknowledgments</A><BR>
  <BR>
  <A HREF="#appendix-a">Appendix A: Sample style sheet for HTML 2.0</A><BR>
  <A HREF="#appendix-b">Appendix B: CSS1 grammar</A><BR>
  <A HREF="#appendix-c">Appendix C: Encoding</A><BR>
  <A HREF="#appendix-d">Appendix D: Gamma correction</A><BR>
  <A HREF="#appendix-e">Appendix E: The applicability and extensibility of
  CSS1</A><BR>
  <H2>
    <A name="terminology">Terminology</A>
  </H2>
  <DL>
    <DT>
      attribute
    <DD>
      HTML attribute
    <DT>
      author
    <DD>
      the author of an HTML document
    <DT>
      block-level element
    <DD>
      an element which has a line break before and after (e.g. 'H1' in HTML)
    <DT>
      canvas
    <DD>
      the part of the UA's drawing surface onto which documents are rendered
    <DT>
      child element
    <DD>
      a <EM>subelement</EM> in SGML <A HREF="#ref5">[5]</A> terminology
    <DT>
      contextual selector
    <DD>
      a selector that matches elements based on their position in the document
      structure. A contextual selector consists of several simple selectors. E.g.,
      the contextual selector 'H1.initial B' consists of two simple selectors,
      'H1.initial' and 'B'.
    <DT>
      CSS
    <DD>
      Cascading Style Sheets
    <DT>
      CSS1
    <DD>
      Cascading Style Sheets, level 1. This document defines CSS1 which is a simple
      style sheet mechanism for the web.
    <DT>
      CSS1 advanced features
    <DD>
      features that are described in this specification but labeled as not among
      the CSS1 core features
    <DT>
      CSS1 core features
    <DD>
      the part of CSS1 that is required in all CSS1 conforming UAs
    <DT>
      CSS1 parser
    <DD>
      a User Agent that reads CSS1 style sheets
    <DT>
      declaration
    <DD>
      a property (e.g. 'font-size') and a corresponding value (e.g. '12pt')
    <DT>
      designer
    <DD>
      the designer of a style sheet
    <DT>
      document
    <DD>
      HTML document
    <DT>
      element
    <DD>
      HTML element
    <DT>
      element type
    <DD>
      a <EM>generic identifier</EM> in SGML <A HREF="#ref5">[5]</A> terminology
    <DT>
      fictional tag sequence
    <DD>
      a tool for describing the behavior of pseudo-classes and pseudo-elements
    <DT>
      font size
    <DD>
      The size for which a font is designed. Typically, the size of a font is
      approximately equal to the distance from the bottom of the lowest letter
      with a descender to the top of the tallest letter with an ascender and
      (optionally) with a diacritical mark.
    <DT>
      HTML
    <DD>
      Hypertext Markup Language <A HREF="#ref2">[2]</A>, an application of SGML.
    <DT>
      HTML extension
    <DD>
      Markup introduced by UA vendors, most often to support certain visual effects.
      The "FONT", "CENTER" and "BLINK" elements are examples of HTML extensions,
      as is the "BGCOLOR" attribute. One of the goals of CSS is to provide an
      alternative to HTML extensions.
    <DT>
      inline element
    <DD>
      an element which does not have a line break before and after (e.g. 'STRONG'
      in HTML)
    <DT>
      intrinsic dimensions
    <DD>
      the width and height as defined by the element itself, not imposed by the
      surroundings. In this specification it is assumed that all replaced elements
      -- and only replaced elements -- come with intrinsic dimensions.
    <DT>
      parent element
    <DD>
      the <EM>containing element</EM> in SGML <A HREF="#ref5">[5]</A> terminology
    <DT>
      pseudo-element
    <DD>
      pseudo-elements are used in CSS selectors to address typographical items
      (e.g. the first line of an element) rather than structural elements.
    <DT>
      pseudo-class
    <DD>
      pseudo-classes are used in CSS selectors to allow information external to
      the HTML source (e.g. the fact that an anchor has been visited or not) to
      classify elements.
    <DT>
      property
    <DD>
      a stylistic parameter that can be influenced through CSS. This specification
      defines a list of properties and their corresponding values.
    <DT>
      reader
    <DD>
      the person for whom the document is rendered
    <DT>
      replaced element
    <DD>
      an element that the CSS formatter only knows the intrinsic dimensions of.
      In HTML, 'IMG', 'INPUT', 'TEXTAREA', 'SELECT' and 'OBJECT' elements can be
      examples of replaced elements. E.g., the content of the 'IMG' element is
      often replaced by the image that the SRC attribute points to. CSS1 does not
      define how the intrinsic dimensions are found.
    <DT>
      rule
    <DD>
      a declaration (e.g. 'font-family: helvetica') and its selector (e.g. 'H1')
    <DT>
      selector
    <DD>
      a string that identifies what elements the corresponding rule applies to.
      A selector can either be a simple selector (e.g. 'H1') or a contextual selector
      (e.g. 'H1 B') which consists of several simple selectors.
    <DT>
      SGML
    <DD>
      Standard Generalized Markup Language <A HREF="#ref5">[5]</A>, of which HTML
      is an application
    <DT>
      simple selector
    <DD>
      a selector that matches elements based on the element type and/or attributes,
      and not he element's position in the document structure. E.g., 'H1.initial'
      is a simple selector.
    <DT>
      style sheet
    <DD>
      a collection of rules
    <DT>
      UA
    <DD>
      User Agent, often a <EM>web browser</EM> or <EM>web client</EM>
    <DT>
      user
    <DD>
      synonymous with <EM>reader</EM>
    <DT>
      weight
    <DD>
      the priority of a rule
  </DL>
  <P>
  In the text of this specification, single quotes ('...') denote HTML and
  CSS excerpts.
  <H2>
    <A NAME="basic-concepts">1 &nbsp;&nbsp; Basic concepts</A>
  </H2>
  <P>
  Designing simple style sheets is easy. One needs only to know a little HTML
  and some basic desktop publishing terminology. E.g., to set the text color
  of 'H1' elements to blue, one can say:
  <PRE>
  H1 { color: blue }
</PRE>
  <P>
  The example above is a simple CSS rule. A rule consists of two main parts:
  selector ('H1') and declaration ('color: blue'). The declaration has two
  parts: property ('color') and value ('blue'). While the example above tries
  to influence only one of the properties needed for rendering an HTML document,
  it qualifies as a style sheet on its own. Combined with other style sheets
  (one fundamental feature of CSS is that style sheets are combined) it will
  determine the final presentation of the document.
  <P>
  The selector is the link between the HTML document and the style sheet, and
  all HTML element types are possible selectors. HTML element types are defined
  in the HTML specification <A HREF="#ref2">[2]</A>.
  <P>
  The <A HREF="#color">'color'</A> property is one of around 50 properties
  that determine the presentation of an HTML document. The list of
  <A HREF="#css1-properties">properties and their possible values</A> is defined
  in this specification.
  <P>
  HTML authors need to write style sheets only if they want to suggest a specific
  style for their documents. Each User Agent (UA, often a "web browser" or
  "web client") will have a default style sheet that presents documents in
  a reasonable -- but arguably mundane -- manner. <A HREF="#appendix-a">Appendix
  A</A> contains a sample style sheet to present HTML documents as suggested
  in the HTML 2.0 specification <A HREF="#ref3">[3]</A>.
  <P>
  The formal grammar for the CSS1 language is defined in
  <A HREF="#appendix-b">Appendix B</A>.
  <H3>
    <A NAME="containment-in-html">1.1 &nbsp;&nbsp; Containment in HTML</A>
  </H3>
  <P>
  In order for the style sheets to influence the presentation, the UA must
  be aware of their existence. The HTML specification <A HREF="#ref2">[2]</A>
  define how to link HTML with style sheets. This section is therefore informative,
  but not normative:
  <PRE>
&lt;HTML&gt;
  &lt;HEAD&gt;
    &lt;TITLE&gt;title&lt;/TITLE&gt;
    &lt;LINK REL=STYLESHEET TYPE="text/css" 
      HREF="http://style.com/cool" TITLE="Cool"&gt;
    &lt;STYLE TYPE="text/css"&gt;
      @import url(http://style.com/basic);
      H1 { color: blue }
    &lt;/STYLE&gt;
  &lt;/HEAD&gt;
  &lt;BODY&gt;
    &lt;H1&gt;Headline is blue&lt;/H1&gt;
    &lt;P STYLE="color: green"&gt;While the paragraph is green.
  &lt;/BODY&gt;
&lt;/HTML&gt;
</PRE>
  <P>
  The example shows four ways to combine style and HTML: using the 'LINK' element
  to link an external style sheet, a 'STYLE' element inside the 'HEAD' element,
  an imported style sheet using the CSS '@import' notation, and a 'STYLE' attribute
  on an element inside 'BODY'. The latter option mixes style with content and
  loses the corresponding advantages of traditional style sheets.
  <P>
  The 'LINK' element references alternative style sheets that the reader can
  select, while imported style sheets are automatically merged with the rest
  of the style sheet.
  <P>
  Traditionally, UAs have silently ignored unknown tags. As as result, old
  UAs will ignore the 'STYLE' element, but its content will be treated as part
  of the document body, and rendered as such. During a transition phase, 'STYLE'
  element content may be hidden using SGML comments:
  <PRE>
  &lt;STYLE TYPE="text/css"&gt;&lt;!--
    H1 { color: green }
  --&gt;&lt;/STYLE&gt;
</PRE>
  <P>
  Since the 'STYLE' element is declared as "CDATA" in the DTD (as defined in
  <A HREF="#ref2">[2]</A>), conforming SGML parsers will not consider the above
  style sheet to be a comment that is to be removed.
  <H3>
    <A NAME="grouping">1.2 &nbsp;&nbsp; Grouping</A>
  </H3>
  <P>
  To reduce the size of style sheets, one can group selectors in comma-separated
  lists:
  <PRE>
  H1, H2, H3 { font-family: helvetica }
</PRE>
  <P>
  Similarly, declarations can be grouped:
  <PRE>
  H1 { 
    font-weight: bold; 
    font-size: 12pt;
    line-height: 14pt; 
    font-family: helvetica; 
    font-variant: normal;
    font-style: normal;
  }
</PRE>
  <P>
  In addition, some properties have their own grouping syntax:
  <PRE>
  H1 { font: bold 12pt/14pt helvetica }
</PRE>
  <P>
  which is equivalent to the previous example.
  <H3>
    <A NAME="inheritance">1.3 &nbsp;&nbsp; Inheritance</A>
  </H3>
  <P>
  In the first example, the color of 'H1' elements was set to blue. Suppose
  there is an 'H1' element with an emphasized element inside:
  <PRE>
  &lt;H1&gt;The headline &lt;EM&gt;is&lt;/EM&gt; important!&lt;/H1&gt;
</PRE>
  <P>
  If no color has been assigned to the 'EM' element, the emphasized "is" will
  inherit the color of the parent element, i.e. it will also appear in blue.
  Other style properties are likewise inherited, e.g.
  <A HREF="#font-family">'font-family'</A> and
  <A HREF="#font-size">'font-size'</A>.
  <P>
  To set a "default" style property for a document, one can set the property
  on an element from which all visible elements descend. In HTML documents,
  the 'BODY' element can serve this function:
  <PRE>
  BODY { 
    color: black;
    background: url(texture.gif) white;
  }
</PRE>
  <P>
  This will work even if the author has omitted the 'BODY' tag (which is legal)
  since the HTML parser will infer the missing tag. The example above sets
  the text color to be black and the background to be an image. The background
  will be white if the image is not available. (See section 5.3 for more on
  this.)
  <P>
  Some style properties are not inherited from the parent element to the child
  element. Most often it is intuitive why this is not the case. E.g., the
  <A HREF="#background">'background'</A> property does not inherit, but the
  parent element's background will shine through by default.
  <P>
  Often, the value of a property is a percentage that refers to another property:
  <PRE>
  P { font-size: 10pt }
  P { line-height: 120% }  /* relative to 'font-size', i.e. 12pt */
</PRE>
  <P>
  For each property that allows percentage values, it is defined what property
  it refers to. Children elements of 'P' will inherit the computed value of
  <A HREF="#line-height">'line-height'</A> (i.e. 12pt), not the
  <A HREF="#percentage-units">percentage</A>.
  <H3>
    <A NAME="class-as-selector">1.4 &nbsp;&nbsp; Class as selector</A>
  </H3>
  <P>
  To increase the granularity of control over elements, a new attribute has
  been added to HTML <A HREF="#ref2">[2]</A>: 'CLASS'. All elements inside
  the 'BODY' element can be classed, and the class can be addressed in the
  style sheet:
  <PRE>
&lt;HTML&gt;
 &lt;HEAD&gt;
  &lt;TITLE&gt;Title&lt;/TITLE&gt;
  &lt;STYLE TYPE="text/css"&gt;
    H1.pastoral { color: #00FF00 }
  &lt;/STYLE&gt;
 &lt;/HEAD&gt;
 &lt;BODY&gt;
  &lt;H1 CLASS=pastoral&gt;Way too green&lt;/H1&gt;
 &lt;/BODY&gt;
&lt;/HTML&gt;
</PRE>
  <P>
  The normal inheritance rules apply to classed elements; they inherit values
  from their parent in the document structure.
  <P>
  One can address all elements of the same class by omitting the tag name in
  the selector:
  <PRE>
  .pastoral { color: green }  /* all elements with CLASS pastoral */
</PRE>
  <P>
  Only one class can be specified per selector. 'P.pastoral.marine' is therefore
  an invalid selector in CSS1. (Contextual selectors, described below, can
  have one class per simple selector)
  <P>
  CSS gives so much power to the CLASS attribute, that in many cases it doesn't
  even matter what HTML element the class is set on -- you can make any element
  emulate almost any other. Relying on this power is not recommended, since
  it removes the level of structure that has a universal meaning (HTML elements).
  A structure based on CLASS is only useful within a restricted domain, where
  the meaning of a class has been mutually agreed upon.
  <H3>
    <A NAME="id-as-selector">1.5 &nbsp;&nbsp; ID as selector</A>
  </H3>
  <P>
  HTML <A HREF="#ref2">[2]</A> also introduces the 'ID' attribute which is
  guaranteed to have a unique value over the document. It can therefore be
  of special importance as a style sheet selector, and can be addressed with
  a preceding '#':
  <PRE>
  #z98y { letter-spacing: 0.3em }
  H1#z98y { letter-spacing: 0.5em }

  &lt;P ID=z98y&gt;Wide text&lt;/P&gt;
</PRE>
  <P>
  In the above example, the first selector matches the 'P' element due to the
  'ID' attribute value. The second selector specifies both an element type
  ('H1') and an ID value, and will therefore not match the 'P' element.
  <P>
  By using the ID attribute as selector, one can set style properties on a
  per-element basis. While style sheets have been designed to augment document
  structure, this feature will allow authors to create documents that present
  well on the canvas without taking advantage of the structural elements of
  HTML. This use of style sheets is discouraged.
  <H3>
    <A NAME="contextual-selectors">1.6 &nbsp;&nbsp; Contextual selectors</A>
  </H3>
  <P>
  Inheritance saves CSS designers typing. Instead of setting all style properties,
  one can create defaults and then list the exceptions. To give 'EM' elements
  within 'H1' a different color, one may specify:
  <PRE>
  H1 { color: blue }
  EM { color: red }
</PRE>
  <P>
  When this style sheet is in effect, all emphasized sections within or outside
  'H1' will turn red. Probably, one wanted only 'EM' elements within 'H1' to
  turn red and this can be specified with:
  <PRE>
  H1 EM { color: red }
</PRE>
  <P>
  The selector is now a search pattern on the stack of open elements, and this
  type of selector is referred to as a <EM>contextual selector</EM>. Contextual
  selectors consist of several simple selectors separated by whitespace (all
  selectors described up to now have been simple selectors). Only elements
  that match the last simple selector (in this case the 'EM' element) are
  addressed, and only if the search pattern matches. Contextual selectors in
  CSS1 look for ancestor relationships, but other relationships (e.g. parent-child)
  may be introduced in later revisions. In the example above, the search pattern
  matches if 'EM' is a descendant of 'H1', i.e. if 'EM' is inside an 'H1' element.
  <PRE>
  UL LI    { font-size: small }    
  UL UL LI { font-size: x-small }
</PRE>
  <P>
  Here, the first selector matches 'LI' elements with at least one 'UL' ancestor.
  The second selector matches a subset of the first, i.e. 'LI' elements with
  at least two 'UL' ancestors. The conflict is resolved by the second selector
  being more specific because of the longer search pattern. See the
  <A HREF="#cascading-order">cascading order (section 3.2)</A> for more on
  this.
  <P>
  Contextual selectors can look for element types, CLASS attributes, ID attributes
  or combinations of these:
  <PRE>
  DIV P           { font: small sans-serif }
  .reddish H1     { color: red }
  #x78y CODE      { background: blue }
  DIV.sidenote H1 { font-size: large }
</PRE>
  <P>
  The first selector matches all 'P' elements that have a 'DIV' among the
  ancestors. The second selector matches matches all 'H1' elements that have
  an ancestor of class 'reddish'. The third selector matches all 'CODE' elements
  that are descendants of the element with 'ID=x78y'. The fourth selector matches
  all 'H1' elements that have a 'DIV' ancestor with class 'sidenote'.
  <P>
  Several contextual selectors can be grouped together:
  <PRE>
  H1 B, H2 B, H1 EM, H2 EM { color: red }
</PRE>
  <P>
  Which is equivalent to:
  <PRE>
  H1 B { color: red }
  H2 B { color: red }
  H1 EM { color: red }
  H2 EM { color: red }
</PRE>
  <H3>
    <A NAME="comments">1.7 &nbsp;&nbsp; Comments</A>
  </H3>
  <P>
  Textual comments in CSS style sheets are similar to those in the C programming
  language <A HREF="#ref7">[7]</A>:
  <PRE>
  EM { color: red }  /* red, really red!! */
</PRE>
  <P>
  Comments cannot be nested. For a CSS1 parser, a comment is equivalent to
  whitespace.
  <H2>
    <A NAME="pseudo-classes-and-pseudo-elements">2 &nbsp;&nbsp; Pseudo-classes
    and pseudo-elements</A>
  </H2>
  <P>
  In CSS1, style is normally attached to an element based on its position in
  the document structure. This simple model is sufficient for a wide variety
  of styles, but doesn't cover some common effects. The concept of pseudo-classes
  and pseudo-elements extend addressing in CSS1 to allow external information
  to influence the formatting process.
  <P>
  Pseudo-classes and pseudo-elements can be used in CSS selectors, but do not
  exist in the HTML source. Rather, they are "inserted" by the UA under certain
  conditions to be used for addressing in style sheets. They are referred to
  as "classes" and "elements" since this is a convenient way of describing
  their behavior. More specifically, their behavior is defined by a <EM>fictional
  tag sequence</EM>.
  <P>
  Pseudo-elements are used to address sub-parts of elements, while pseudo-classes
  allow style sheets to differentiate between different element types.
  <H3>
    <A NAME="anchor-pseudo-classes">2.1 &nbsp;&nbsp; Anchor pseudo-classes</A>
  </H3>
  <P>
  User agents commonly display newly visited anchors differently from older
  ones. In CSS1, this is handled through pseudo-classes on the 'A' element:
  <PRE>
  A:link { color: red }       /* unvisited link */
  A:visited { color: blue }   /* visited links */
  A:active { color: lime }    /* active links */
</PRE>
  <P>
  All 'A' elements with an 'HREF' attribute will be put into one and only one
  of these groups (i.e. target anchors are not affected). UAs may choose to
  move an element from 'visited' to 'link' after a certain time. An 'active'
  link is one that is currently being selected (e.g. by a mouse button press)
  by the reader.
  <P>
  The formatting of an anchor pseudo-class is as if the class had been inserted
  manually. A UA is not required to reformat a currently displayed document
  due to anchor pseudo-class transitions. E.g., a style sheet can legally specify
  that the 'font-size' of an 'active' link should be larger that a 'visited'
  link, but the UA is not required to dynamically reformat the document when
  the reader selects the 'visited' link.
  <P>
  Pseudo-class selectors do not match normal classes, and vice versa. The style
  rule in the example below will therefore not have any influence:
  <PRE>
  A:link { color: red }

  &lt;A CLASS=link NAME=target5&gt; ... &lt;/A&gt;
</PRE>
  <P>
  In CSS1, anchor pseudo-classes have no effect on elements other than 'A'.
  Therefore, the element type can be omitted from the selector:
  <PRE>
  A:link { color: red }
  :link { color: red }
</PRE>
  <P>
  The two selectors above will select the same elements in CSS1.
  <P>
  Pseudo-class names are case-insensitive.
  <P>
  Pseudo-classes can be used in contextual selectors:
  <PRE>
  A:link IMG { border: solid blue }
</PRE>
  <P>
  Also, pseudo-classes can be combined with normal classes:
  <PRE>
  A.external:visited { color: blue }

  &lt;A CLASS=external HREF="http://out.side/"&gt;external link&lt;/A&gt;
</PRE>
  <P>
  If the link in the above example has been visited, it will be rendered in
  blue. Note that normal class names precede pseudo-classes in the selector.
  <H3>
    <A NAME="typographical-pseudo-elements">2.2 &nbsp;&nbsp; Typographical
    pseudo-elements</A>
  </H3>
  <P>
  Some common typographical effects are associated not with structural elements
  but rather with typographical items as formatted on the canvas. In CSS1,
  two such typographical items can be addressed through pseudo-elements: the
  first line of an element, and the first letter.
  <P>
  <EM>CSS1 core:</EM> UAs may ignore all rules with ':first-line' or
  ':first-letter' in the selector, or, alternatively, only support a subset
  of the properties on these pseudo-elements. (see
  <A href="#css1-conformance">section 7</A>)
  <H3>
    <A NAME="the-first-line-pseudo-element">2.3 &nbsp;&nbsp; The 'first-line'
    pseudo-element</A>
  </H3>
  <P>
  The 'first-line' pseudo-element is used to apply special styles to the first
  line as formatted on the canvas:
  <PRE>
  &lt;STYLE TYPE="text/css"&gt;
    P:first-line { font-style: small-caps }
  &lt;/STYLE&gt;

  &lt;P&gt;The first line of an article in Newsweek.
</PRE>
  <P>
  On a text-based UA, this could be formatted as:
  <PRE>
  THE FIRST LINE OF AN
  article in Newsweek.
</PRE>
  <P>
  The fictional tag sequence in the above example is:
  <PRE>
  &lt;P&gt;
  &lt;P:first-line&gt;
  The first line of an 
  &lt;/P:first-line&gt;
  article in Newsweek.
  &lt;/P&gt;
</PRE>
  <P>
  The 'first-line' end tag is inserted at the end of the first line as formatted
  on the canvas.
  <P>
  The 'first-line' pseudo-element can only be attached to a block-level element.
  <P>
  The 'first-line' pseudo-element is similar to an inline element, but with
  certain restrictions. Only the following properties apply to a 'first-line'
  element: font properties (<A href="#font-properties">5.2</A>), color and
  background properties (<A href="#color-and-background-properties">5.3</A>),
  'word-spacing' (<A href="#word-spacing">5.4.1</A>), 'letter-spacing'
  (<A href="#letter-spacing">5.4.2</A>), 'text-decoration'
  (<A href="#text-decoration">5.4.3</A>), 'vertical-align
  (<A href="#vertical-align">5.4.4</A>), 'text-transform'
  (<A href="#text-transform">5.4.5</A>), 'line-height'
  (<A href="#line-height">5.4.8</A>), 'clear' (<A href="#clear">5.5.26</A>).
  <H3>
    <A NAME="the-first-letter-pseudo-element">2.4 &nbsp;&nbsp; The 'first-letter'
    pseudo-element</A>
  </H3>
  <P>
  The 'first-letter' pseudo-element is used for "initial caps" and "drop caps",
  which are common typographical effects. It is similar to an inline element
  if its 'float' property is 'none', otherwise it is similar to a floating
  element. These are the properties that apply to 'first-letter' pseudo-elements:
  font properties (<A href="#font-properties">5.2</A>), color and background
  properties (<A href="#color-and-background-properties">5.3</A>),
  'text-decoration' (<A href="#text-decoration">5.4.3</A>), 'vertical-align
  (only if 'float' is 'none', <A href="#vertical-align">5.4.4</A>),
  'text-transform' (<A href="#text-transform">5.4.5</A>), 'line-height'
  (<A href="#line-height">5.4.8</A>), margin properties
  (<A href="#margin-top">5.5.1</A>-<A href="#margin">5.5.5</A>), padding properties
  (<A href="#padding-top">5.5.6</A>-<A href="#padding">5.5.10</A>), border
  properties
  (<A href="#border-top-width">5.5.11</A>-<A href="#border">5.5.22</A>), 'float'
  (<A href="#float">5.5.25</A>), 'clear' (<A href="#clear">5.5.26</A>).
  <P>
  This is how you could make a dropcap initial letter span two lines:
  <PRE>
&lt;HTML&gt;
 &lt;HEAD&gt;
  &lt;TITLE&gt;Title&lt;/TITLE&gt;
  &lt;STYLE TYPE="text/css"&gt;
   P              { font-size: 12pt; line-height: 12pt }
   P:first-letter { font-size: 200%; float: left }
   SPAN           { text-transform: uppercase }
  &lt;/STYLE&gt;
 &lt;/HEAD&gt;
 &lt;BODY&gt;
  &lt;P&gt;&lt;SPAN&gt;The first&lt;/SPAN&gt; few words of an article in The Economist.&lt;/P&gt;
 &lt;/BODY&gt;
&lt;/HTML&gt;
</PRE>
  <P>
  If a text-based UA supports the 'first-letter' pseudo-element (they probably
  will not), the above could be formatted as:
  <PRE>
  ___
   | HE FIRST few
   | words of an 
  article in the
  Economist.
</PRE>
  <P>
  The fictional tag sequence is:
  <PRE>
  &lt;P&gt;
  &lt;SPAN&gt;
  &lt;P:first-letter&gt;
  T
  &lt;/P:first-letter&gt;he first
  &lt;/SPAN&gt; 
  few words of an article in the Economist.
  &lt;/P&gt;
</PRE>
  <P>
  Note that the 'first-letter' pseudo-element tags abut the content (i.e. the
  initial character), while the 'first-line' pseudo-element start tag is inserted
  right after the start tag of the element it is attached to.
  <P>
  The UA defines what characters are inside the 'first-letter' element. Normally,
  quotes that precede the first letter should be included:
  <PRE>
  ||   /\    bird in 
      /  \   the hand
     /----\  is worth
    /      \ two in
  the bush," says an 
  old proverb.
</PRE>
  <P>
  When the paragraph starts with other punctuation (e.g. parenthesis and ellipsis
  points) or other characters that are normally not considered letters (e.g.
  digits and mathematical symbols), 'first-letter' pseudo-elements are usually
  ignored.
  <P>
  Some languages may have specific rules about how to treat certain letter
  combinations. In Dutch, for example, if the letter combination "ij" appears
  at the beginning of a word, they should both be considered within the
  'first-letter' pseudo-element.
  <P>
  The 'first-letter' pseudo-element can only be attached to a block-level element.
  <H3>
    <A NAME="pseudo-elements-in-selectors">2.5 &nbsp;&nbsp; Pseudo-elements in
    selectors</A>
  </H3>
  <P>
  In a contextual selector, pseudo-elements are only allowed at the end of
  the selector:
  <PRE>
  BODY P:first-letter { color: purple }
</PRE>
  <P>
  Pseudo-elements can be combined with classes in selectors:
  <PRE>
  P.initial:first-letter { color: red }

  &lt;P CLASS=initial&gt;First paragraph&lt;/A&gt;
</PRE>
  <P>
  The above example would make the first letter of all 'P' elements with
  'CLASS=initial' red. When combined with classes or pseudo-classes,
  pseudo-elements must be specified at the end of the selector. Only one
  pseudo-element can be specified per selector.
  <H3>
    <A NAME="multiple-pseudo-elements">2.6 &nbsp;&nbsp; Multiple
    pseudo-elements</A>
  </H3>
  <P>
  Several pseudo elements can be combined:
  <PRE>
  P { color: red; font-size: 12pt }
  P:first-letter { color: green; font-size: 200% }
  P:first-line { color: blue }

  &lt;P&gt;Some text that ends up on two lines&lt;/P&gt;
</PRE>
  <P>
  In this example, the first letter of each 'P' element would be green with
  a font size of 24pt. The rest of the first line (as formatted on the canvas)
  would be blue while the rest of the paragraph would be red. Assuming that
  a line break will occur before the word "ends", the fictional tag sequence
  is:
  <PRE>
  &lt;P&gt;
  &lt;P:first-line&gt;
  &lt;P:first-letter&gt; 
  S 
  &lt;/P:first-letter&gt;ome text that 
  &lt;/P:first-line&gt; 
  ends up on two lines 
  &lt;/P&gt;
</PRE>
  <P>
  Note that the 'first-letter' element is inside the 'first-line' element.
  Properties set on 'first-line' will be inherited by 'first-letter', but are
  overridden if the same property is set on 'first-letter'.
  <P>
  If a pseudo-element breaks up a real element the necessary extra tags must
  be regenerated in the fictional tag sequence. For example, if a SPAN element
  spans over a <TT>&lt;/P:first-line&gt;</TT> tag, a set of SPAN end and start
  tags must be regenerated and the fictional tag sequence becomes:
  <PRE>
  &lt;P&gt;
  &lt;P:first-line&gt;
  &lt;SPAN&gt; 
  This text is inside a long 
  &lt;/SPAN&gt;
  &lt;/P:first-line&gt;
  &lt;SPAN&gt; 
  span element 
  &lt;/SPAN&gt;
</PRE>
  <H2>
    <A NAME="the-cascade">3 &nbsp;&nbsp; The cascade</A>
  </H2>
  <P>
  In CSS, more than one style sheet can influence the presentation simultaneously.
  There are two main reasons for this feature: modularity and author/reader
  balance.
  <DL>
    <DT>
      modularity
    <DD>
      A style sheet designer can combine several (partial) style sheets to reduce
      redundancy:
      <PRE>
  @import url(http://www.style.org/pastoral);
  @import url(http://www.style.org/marine);

  H1 { color: red }     /* override imported sheets */
</PRE>
    <DT>
      author/reader balance
    <DD>
      Both readers and authors can influence the presentation through style sheets.
      To do so, they use the same style sheet language thus reflecting a fundamental
      feature of the web: everyone can become a publisher. The UA is free to choose
      the mechanism for referencing personal style sheets.
  </DL>
  <P>
  Sometimes conflicts will arise between the style sheets that influence the
  presentation. Conflict resolution is based on each style rule having a weight.
  By default, the weights of the reader's rules are less than the weights of
  rules in the author's documents. I.e., if there are conflicts between the
  style sheets of an incoming document and the reader's personal sheets, the
  author's rules will be used. Both reader and author rules override the UA's
  default values.
  <P>
  The imported style sheets also cascade with each other, in the order they
  are imported, according to the cascading rules defined below. Any rules specified
  in the style sheet itself override rules in imported style sheets. That is,
  imported style sheets are lower in the cascading order than rules in the
  style sheet itself. Imported style sheets can themselves import and override
  other style sheets, recursively.
  <P>
  In CSS1, all '@import' statements must occur at the start of a style sheet,
  before any declarations. This makes it easy to see that rules in the style
  sheet itself override rules in the imported style sheets.
  <H3>
    <A NAME="important">3.1 &nbsp;&nbsp; 'important'</A>
  </H3>
  <P>
  Style sheet designers can increase the weights of their declarations:
  <PRE>
  H1 { color: black ! important; background: white ! important }
  P  { font-size: 12pt ! important; font-style: italic }
</PRE>
  <P>
  In the example above, the first three declarations have increased weight,
  while the last declaration has normal weight.
  <P>
  A reader rule with an important declaration will override an author rule
  with a normal declaration. An author rule with an important declaration will
  override a reader rule with an important declaration.
  <H3>
    <A NAME="cascading-order">3.2 &nbsp;&nbsp; Cascading order</A>
  </H3>
  <P>
  Conflicting rules are intrinsic to the CSS mechanism. To find the value for
  an element/property combination, the following algorithm must be followed:
  <OL>
    <LI>
      Find all declarations that apply to the element/property in question.
      Declarations apply if the selector matches the element in question. If no
      declarations apply, the inherited value is used. If there is no inherited
      value (this is the case for the 'HTML' element and for properties that do
      not inherit), the initial value is used.
    <LI>
      Sort the declarations by explicit weight: declarations marked '!important'
      carry more weight than unmarked (normal) declarations.
    <LI>
      Sort by origin: the author's style sheets override the reader's style sheet
      which override the UA's default values. An imported style sheet has the same
      origin as the style sheet from which it is imported.
    <LI>
      Sort by specificity of selector: more specific selectors will override more
      general ones. To find the specificity, count the number of ID attributes
      in the selector (a), the number of CLASS attributes in the selector (b),
      and the number of tag names in the selector (c). Concatenating the three
      numbers (in a number system with a large base) gives the specificity. Some
      examples:
      <PRE>
  LI            {...}  /* a=0 b=0 c=1 -&gt; specificity =   1 */
  UL LI         {...}  /* a=0 b=0 c=2 -&gt; specificity =   2 */
  UL OL LI      {...}  /* a=0 b=0 c=3 -&gt; specificity =   3 */
  LI.red        {...}  /* a=0 b=1 c=1 -&gt; specificity =  11 */
  UL OL LI.red  {...}  /* a=0 b=1 c=3 -&gt; specificity =  13 */ 
  #x34y         {...}  /* a=1 b=0 c=0 -&gt; specificity = 100 */ 
</PRE>
      <P>
      Pseudo-elements and pseudo-classes are counted as normal elements and classes,
      respectively.
    <LI>
      Sort by order specified: if two rules have the same weight, the latter specified
      wins. Rules in imported style sheets are considered to be before any rules
      in the style sheet itself.
  </OL>
  <P>
  The search for the property value can be terminated whenever one rule has
  a higher weight than the other rules that apply to the same element/property
  combination.
  <P>
  This strategy gives author's style sheets considerably higher weight than
  those of the reader. It is therefore important that the reader has the ability
  to turn off the influence of a certain style sheet, e.g. through a pull-down
  menu.
  <P>
  A declaration in the 'STYLE' attribute of an element (see
  <A HREF="#containment-in-html">section 1.1</A> for an example) has the same
  weight as a declaration with an ID-based selector that is specified at the
  end of the style sheet:
  <PRE>
&lt;STYLE TYPE="text/css"&gt;
  #x97z { color: blue }
&lt;/STYLE&gt;

&lt;P ID=x97z STYLE="color: red"&gt;
</PRE>
  <P>
  In the above example, the color of the 'P' element would be red. Although
  the specificity is the same for both declarations, the declaration in the
  'STYLE' attribute will override the one in the 'STYLE' element because of
  cascading rule number 5.
  <P>
  The UA may choose to honor other stylistic HTML attributes, for example 'ALIGN'.
  If so, these attributes are translated to the corresponding CSS rules with
  specificity equal to 1. The rules are assumed to be at the start of the author
  style sheet and may be overridden by subsequent style sheet rules. In a
  transition phase, this policy will make it easier for stylistic attributes
  to coexist with style sheets.
  <H2>
    <A NAME="formatting-model">4 &nbsp;&nbsp; Formatting model</A>
  </H2>
  <P>
  CSS1 assumes a simple box-oriented formatting model where each element results
  in one or more rectangular boxes. (Elements that have a 'display' value of
  'none' are not formatted and will therefore not result in a box.) All boxes
  have a core content area with optional surrounding padding, border and margin
  areas.
  <PRE>
    _______________________________________
   |                                       |
   |           margin (transparent)        |
   |   _________________________________   |
   |  |                                 |  |
   |  |        border                   |  |
   |  |   ___________________________   |  |
   |  |  |                           |  |  |
   |  |  |     padding               |  |  |
   |  |  |   _____________________   |  |  |
   |  |  |  |                     |  |  |  |
   |  |  |  |  content            |  |  |  |
   |  |  |  |_____________________|  |  |  |
   |  |  |___________________________|  |  |
   |  |_________________________________|  |
   |_______________________________________|

            |    element width    |

   |               box width               |

</PRE>
  <P>
  The size of the margin, border and padding are set with the margin
  (<A href="#margin-top">5.5.1</A>-<A href="#margin">5.5.5</A>), padding
  (<A href="#padding-top">5.5.6</A>-<A href="#padding">5.5.10</A>), and border
  (<A href="#border-top-width">5.5.11</A>-<A href="#border">5.5.22</A>) properties
  respectively. The padding area uses the same background as the element itself
  (set with the background properties
  (<A href="#background-color">5.3.2</A>-<A href="#background">5.3.7</A>).
  The color and style for the border is set with the border properties. The
  margins are always transparent, so the parent element will shine through.
  <P>
  The size of the box is the sum of the element width (i.e. formatted text
  or image) and the padding, the border and the margin areas.
  <P>
  From the formatter's point of view there are two main types of elements:
  block-level and inline.
  <H3>
    <A NAME="block-level-elements">4.1 &nbsp;&nbsp; Block-level elements</A>
  </H3>
  <P>
  Elements with a 'display' value of 'block' or 'list-item' are
  <EM>block-level</EM> elements. Also, floating elements (elements with a 'float'
  value other than 'none') are considered to be block-level elements.
  <P>
  The following example shows how margins and padding format a 'UL' element
  with two children. To simplify the diagram there are no borders. Also, the
  single-letter "constants" in this example are not legal CSS1 syntax, but
  is a convenient way to tie the style sheet values to the figure.
  <PRE>
    &lt;STYLE TYPE="text/css"&gt;
      UL { 
        background: red; 
        margin: A B C D;      
        padding: E F G H;
      }
      LI { 
        color: white;    
        background: blue;     /* so text is white on blue */ 
        margin: a b c d; 
        padding: e f g h;
      }
    &lt;/STYLE&gt;
    ..
    &lt;UL&gt;
      &lt;LI&gt;1st element of list
      &lt;LI&gt;2nd element of list
    &lt;/UL&gt;
</PRE>
  <PRE>
   _______________________________________________________
  |                                                       |
  |    A      UL margin (transparent)                     |
  |    _______________________________________________    |
  | D |                                               | B |
  |   |    E   UL padding (red)                       |   |
  |   |    _______________________________________    |   |
  |   | H |                                       | F |   |
  |   |   |    a   LI margin (transparent,        |   |   |
  |   |   |        so red shines through)         |   |   |
  |   |   |    _______________________________    |   |   |
  |   |   | d |                               | b |   |   |
  |   |   |   |    e    LI padding (blue)     |   |   |   |
  |   |   |   |                               |   |   |   |
  |   |   |   | h  1st element of list      f |   |   |   |
  |   |   |   |                               |   |   |   |
  |   |   |   |    g                          |   |   |   |
  |   |   |   |_______________________________|   |   |   |
  |   |   |                                       |   |   |
  |   |   |     max(a, c)                         |   |   | &lt;- note the max
  |   |   |    _______________________________    |   |   |
  |   |   |   |                               |   |   |   |
  |   |   | d |    e    LI padding (blue)     |   |   |   |
  |   |   |   |                               |   |   |   |
  |   |   |   | h  2nd element of list      f |   |   |   |
  |   |   |   |                               |   |   |   |
  |   |   |   |    g                          |   |   |   |
  |   |   |   |_______________________________|   |   |   |
  |   |   |                                       |   |   |
  |   |   |   c    LI margin (transparent,        |   |   |
  |   |   |        so red shines through)         |   |   |
  |   |   |_______________________________________|   |   |
  |   |                                               |   |
  |   |    G                                          |   |
  |   |_______________________________________________|   |
  |                                                       |
  |   C                                                   |
  |_______________________________________________________|
</PRE>
  <P>
  Technically, padding and margin properties are not inherited. But, as the
  example shows, the placement of an element is relative to ancestors and siblings,
  so these elements' padding and margin properties have an effect on their
  children.
  <P>
  If there had been borders in the above example they would have appeared between
  the padding and the margins.
  <P>
  The following diagram introduces some useful terminology:
  <PRE>
                               --------------- <B>&lt;-- top</B>
                                 top margin
                               ---------------
                                 top border
                               ---------------
                                top padding
                               +-------------+ <B>&lt;-- inner top</B>
    |        |        |        |             |         |         |         |
    |--left--|--left--|--left--|-- content --|--right--|--right--|--right--|
    | margin | border | padding|             | padding | border  | margin  |
    |        |        |        |             |         |         |         |
                               +-------------+ <B>&lt;-- inner bottom</B>
    <B>^</B>                          <B>^</B>             <B>^</B>                             <B>^</B>
    <B>left</B>         <B>left inner edge</B>             <B>right inner edge</B>          <B>right</B>
    <B>outer</B>                                                              <B>outer</B>
    <B>edge</B>                        bottom padding                          <B>edge</B>
                               ---------------
                                 bottom border
                               ---------------
                                 bottom margin
                               --------------- <B>&lt;-- bottom</B>
</PRE>
  <P>
  The <EM>left outer edge</EM> is the edge of an element with its padding,
  border and margin taken into account. The <EM>left inner edge</EM> is the
  edge of the content only, inside any padding, border or margin. Ditto for
  right. The <EM>top</EM> is the top of the object including any padding, border
  and margin; it is only defined for inline and floating elements, not for
  non-floating block-level elements. The <EM>inner top</EM> is the top of the
  content, inside any padding, border or margin. The <EM>bottom</EM> is the
  bottom of the element, outside any padding border and margin; it is only
  defined for inline and floating elements, not for non-floating block-level
  elements. The <EM>inner bottom</EM> is the bottom of the element, inside
  any padding, border and margin.
  <P>
  The <EM>width</EM> of an element is the width of the content, i.e., the distance
  between left inner edge and right inner edge. The <EM>height</EM> is the
  height of the content, i.e., the distance from inner top to inner bottom.
  <H4>
    <A NAME="vertical-formatting">4.1.1 &nbsp;&nbsp; Vertical formatting</A>
  </H4>
  <P>
  The width of the margin on non-floating block-level elements specifies the
  minimum distance to the edges of surrounding boxes. Two or more adjoining
  vertical margins (i.e., with no border, padding or content between them)
  are collapsed to use the maximum of the margin values. In most cases, after
  collapsing the vertical margins the result is visually more pleasing and
  closer to what the designer expects. In the example above, the margins between
  the two 'LI' elements are collapsed by using the maximum of the first LI
  element's 'margin-bottom' and the second LI element's 'margin-top'. Similarly,
  if the padding between the 'UL' and the first 'LI' element (the "E" constant)
  had been zero, the margins of the UL and first LI elements would have been
  collapsed.
  <P>
  In the case of negative margins, the absolute maximum of the negative adjoining
  margins is deducted from the maximum of the positive adjoining margins. If
  there are no positive margins, the absolute maximum of the negative adjoining
  margins is deducted from zero.
  <H4>
    <A NAME="horizontal-formatting">4.1.2 &nbsp;&nbsp; Horizontal formatting</A>
  </H4>
  <P>
  The horizontal position and size of a non-floating, block-level element is
  determined by seven properties: 'margin-left', 'border-left', 'padding-left',
  'width', 'padding-right', 'border-right' and 'margin-right'. The sum of these
  seven is always equal to the 'width' of the parent element.
  <P>
  By default, the 'width' of an element is 'auto'. If the element is not a
  replaced element, this means that the 'width' is calculated by the UA so
  that the sum of the seven properties mentioned above is equal to the parent
  width. If the element is a replaced element, a value of 'auto' for 'width'
  is automatically replaced by the element's intrinsic width.
  <P>
  Three of the seven properties can be set to 'auto': 'margin-left', 'width'
  and 'margin-right'. For replaced elements, a value of 'auto' on 'width' is
  replaced by the intrinsic width, so for them there can only be two 'auto'
  values.
  <P>
  The 'width' has a non-negative UA-defined minimum value (which may vary from
  element to element and even depend on other properties). If 'width' goes
  below this limit, either because it was set explicitly, or because it was
  'auto' and the rules below would make it too small, the value will be replaced
  with the minimum value instead.
  <P>
  If <EM>exactly one</EM> of 'margin-left', 'width' or 'margin-right' is 'auto',
  the UA will assign that property a value that will make the sum of the seven
  equal to the parent's width.
  <P>
  If <EM>none</EM> of the properties are 'auto', the value of 'margin-right'
  will be assigned 'auto'.
  <P>
  If <EM>more than one</EM> of the three is 'auto', and one of them is 'width',
  than the others ('margin-left' and/or 'margin-right') will be set to zero
  and 'width' will get the value needed to make the sum of the seven equal
  to the parent's width.
  <P>
  Otherwise, if both 'margin-left' and 'margin-right' are 'auto', they will
  be set to equal values. This will center the element inside its parent.
  <P>
  If 'auto' is set as the value for one of the seven properties in an element
  that is inline or floating, it will be treated as if it were set to zero.
  <P>
  Unlike vertical margins, horizontal margins are not collapsed.
  <H3>
    <A NAME="list-item-elements">4.1.3 &nbsp;&nbsp; List-item elements</A>
  </H3>
  <P>
  Elements with a 'display' property value of 'list-item' are formatted as
  block-level elements, but preceded by a list-item marker. The type of marker
  is determined by the 'list-style' property. The marker is placed according
  to the value of the <A HREF="#list-style">'list-style'</A> property:
  <PRE>
  &lt;STYLE TYPE="text/css"&gt;
    UL         { list-style: outside }
    UL.compact { list-style: inside }
  &lt;/STYLE&gt;
  
  &lt;UL&gt;
    &lt;LI&gt;first list item comes first
    &lt;LI&gt;second list item comes second
  &lt;/UL&gt;

  &lt;UL CLASS=COMPACT&gt;
    &lt;LI&gt;first list item comes first
    &lt;LI&gt;second list item comes second
  &lt;/UL&gt;
</PRE>
  <P>
  The above example may be formatted as:
  <PRE>
  * first list item 
    comes first

  * second list item
    comes second


  * first list
  item comes first

  * second list
  item comes second
</PRE>
  <P>
  In right-to-left text, the markers would have been on the right side of the
  box.
  <H3>
    <A NAME="floating-elements">4.1.4 &nbsp;&nbsp; Floating elements</A>
  </H3>
  <P>
  Using the <A HREF="#float">'float'</A> property, an element can be declared
  to be outside the normal flow of elements and is then formatted as a block-level
  element. For example, by setting the 'float' property of an image to 'left',
  the image is moved to the left until the margin, padding or border of another
  block-level element is reached. The normal flow will wrap around on the right
  side. The margins, borders and padding of the element itself will be honored,
  and the margins never collapse with the margins of adjacent elements.
  <P>
  A floating element is positioned subject to the following constraints (see
  <A href="#block-level-elements">section 4.1</A> for an explanation of the
  terms):
  <OL>
    <LI>
      The left outer edge of a left-floating element may not be to the left of
      the left inner edge of its parent element. Analogously for right floating
      elements.
    <LI>
      The left outer edge of a left floating element must be to the right of the
      right outer edge of every earlier (in the HTML source) left-floating element
      or the top of the former must be lower than the bottom of the latter. Analogously
      for right floating elements.
    <LI>
      The right outer edge of a left-floating element may not be to the right of
      the left outer edge of any right-floating element that is to the right of
      it. Analogously for right-floating elements.
    <LI>
      A floating element's top may not be higher than the inner top of its parent.
    <LI>
      A floating element's top may not be higher than the top of any earlier floating
      or block-level element.
    <LI>
      A floating element's top may not be higher than the top of any
      <EM>line-box</EM> (see section 4.4) with content that precedes the floating
      element in the HTML source.
    <LI>
      A floating element must be placed as high as possible.
    <LI>
      A left-floating element must be put as far to the left as possible, a
      right-floating element as far to the right as possible. A higher position
      is preferred over one that is further to the left/right.
  </OL>
  <PRE>
  &lt;STYLE TYPE="text/css"&gt;
    IMG { float: left }
    BODY, P, IMG { margin: 2em }
  &lt;/STYLE&gt;

  &lt;BODY&gt;
    &lt;P&gt;
      &lt;IMG SRC=img.gif&gt;
      Some sample text that has no other...
  &lt;/BODY&gt;
</PRE>
  <P>
  The above example could be formatted as:
  <PRE>
   ________________________________________
  |
  |          max(BODY margin, P margin)
  |          ______________________________
  |    |    |             Some sample text
  | B  | P  | IMG margins that has no other
  | O  |    |    _____    purpose than to 
  | D  | m  |   |     |   show how floating
  | Y  | a  |   | IMG |   elements are moved
  |    | r  |   |     |   to the side of the
  | m  | g  |   |_____|   parent element
  | a  | i  |             while honoring
  | r  | n  |             margins, borders
  | g  |    |             and padding. Note
  | i  |    |how adjacent vertical margins  
  | n  |    |are collapsed between non-
  |    |    |floating block-level elements.
</PRE>
  <P>
  Note that the margin of the 'P' elements enclose the floating 'IMG' element.
  <P>
  There are two situations when floating elements can overlap with the margin,
  border and padding areas of other elements:
  <UL>
    <LI>
      when the floating element has a negative margin: negative margins on floating
      elements are honored as on other block-level elements.
    <LI>
      when the floating element is wider or higher than the element it is inside
  </UL>
  <H3>
    <A NAME="inline-elements">4.2 &nbsp;&nbsp; Inline elements</A>
  </H3>
  <P>
  Elements that are not formatted as block-level elements are <EM>inline</EM>
  elements. An inline element can share line space with other elements. Consider
  this example:
  <PRE>
  &lt;P&gt;Several &lt;EM&gt;emphasized&lt;/EM&gt; words &lt;STRONG&gt;appear&lt;/STRONG&gt;.&lt;/P&gt;
</PRE>
  <P>
  The 'P' element is normally block-level, while 'EM' and 'STRONG' are inline
  elements. If the 'P' element is wide enough to format the whole element on
  one line, there will be two inline elements on the line:
  <PRE>
  Several <EM>emphasized</EM> words <STRONG>appear</STRONG>.
</PRE>
  <P>
  If there is not enough room on one line an inline element will be split into
  several boxes:
  <PRE>
  &lt;P&gt;Several &lt;EM&gt;emphasized words&lt;/EM&gt; appear here.&lt;/P&gt;
</PRE>
  <P>
  The above example may be formatted as:
  <PRE>
  Several <EM>emphasized</EM>
  <EM>words</EM> appear here.
</PRE>
  <P>
  If the inline element has margins, borders, padding or text decorations attached,
  these will have no effect where the element is broken:
  <PRE>
           ----------
  Several |<EM>emphasized</EM>
           ----------
  -----
  <EM>words</EM>| appear here.
  -----
</PRE>
  <P>
  (The "figure" above is slightly distorted due to the use of ASCII graphics.
  See <A HREF="#the-height-of-lines">section 4.4</A> for a description of how
  to calculate the height of lines.
  <H3>
    <A NAME="replaced-elements">4.3 &nbsp;&nbsp; Replaced elements</A>
  </H3>
  <P>
  A replaced element is an element which is replaced by content pointed to
  from the element. E.g., in HTML, the 'IMG' element is replaced by the image
  pointed to by the 'SRC' attribute. One can assume that replaced elements
  come with their own intrinsic dimensions. If the value of the 'width' property
  is 'auto', the intrinsic width is used as the width of the element. If a
  value other than 'auto' is specified in the style sheet, this value is used
  and the replaced element is resized accordingly (the resize method will depend
  on the media type). The 'height' property is used in the same manner.
  <P>
  Replaced elements can be either block-level or inline.
  <H3>
    <A NAME="the-height-of-lines">4.4 &nbsp;&nbsp; The height of lines</A>
  </H3>
  <P>
  All elements have a 'line-height' property that, in principle, gives the
  total height of a line of text. Space is added above and below the text of
  the line to arrive at that line height. For example, if the text is 12pt
  high and 'line-height' is set to '14pt', an extra space of 2pt is added,
  namely 1pt above and 1pt below the line. Empty elements influence these
  calculations just like elements with content.
  <P>
  The difference between the font size and the 'line-height' is called the
  <EM>leading</EM>. Half the leading is called the <EM>half-leading</EM>. After
  formatting, each line will form a rectangular <EM>line-box</EM>.
  <P>
  If a line of text contains sections with different 'line-height' values (because
  there are inline elements on the line), then each of those sections has its
  own half-leading above and below. The height of the line-box is from the
  top of the highest section to the bottom of the lowest one. Note that the
  top and bottom do not necessarily correspond to the tallest element, since
  elements can be positioned vertically with the
  <A HREF="#vertical-align">'vertical-align'</A> property. To form a paragraph,
  each line-box is stacked immediately below the previous line.
  <P>
  Note that any padding, border or margin above and below non-replaced inline
  elements does not influence the height of the line. In other words: if the
  'line-height' is too small for the chosen padding or border, it will overlap
  with text on other lines.
  <P>
  Replaced elements (e.g. images) on the line can make the line-box bigger,
  if the top of the replaced element (i.e., including all of its padding, border
  and margin) is above the tallest text section, or if the bottom is below
  the lowest.
  <P>
  In the normal case, when there is only one value of 'line-height' throughout
  a paragraph, and no tall images, the definition above will ensure that baselines
  of successive lines are exactly 'line-height' apart. This is important when
  columns of text in different fonts have to be aligned, for example in a table.
  <P>
  Note that this doesn't preclude the text on two adjacent lines from overlapping
  each other. The 'line-height' may be smaller than the height of the text,
  in which case the leading will be negative. This is useful if you know that
  the text will contain no descenders (e.g., because it only contains uppercase),
  so the lines can be put closer together.
  <H3>
    <A NAME="the-canvas">4.5 &nbsp;&nbsp; The canvas</A>
  </H3>
  <P>
  The canvas is the part of the UA's drawing surface onto which documents are
  rendered. No structural element of a document corresponds to the canvas,
  and this raises two issues when formatting a document:
  <UL>
    <LI>
      from where should the dimensions of the canvas be set?
    <LI>
      when the document doesn't cover the whole canvas, how should this area be
      rendered?
  </UL>
  <P>
  A reasonable answer to the first question is that the initial size of the
  canvas is based on the window size, but CSS1 leaves this issue for the UA
  to decide. It is also reasonable to expect the UA to change the canvas size
  when the window is resized, but this is also outside the scope of CSS1.
  <P>
  HTML extensions have set a precedent for the second question: attributes
  on the 'BODY' element set the background of the whole canvas. To support
  designers' expectations, CSS1 introduces a special rule to find the canvas
  background:
  <BLOCKQUOTE>
    If the 'background' value of the 'HTML' element is different from 'transparent'
    then use it, else use the 'background' value of the 'BODY' element. If the
    resulting value is 'transparent', the rendering is undefined.
  </BLOCKQUOTE>
  <P>
  This rule allows:
  <PRE>
  &lt;HTML STYLE="background: url(http://style.com/marble.png)"&gt;
  &lt;BODY STYLE="background: red"&gt;
</PRE>
  <P>
  In the example above, the canvas will be covered with "marble". The background
  of the 'BODY' element (which may or may not fully cover the canvas) will
  be red.
  <P>
  Until other means of addressing the canvas become available, it is recommended
  that canvas properties are set on the 'BODY' element.
  <H3>
    <A NAME="br-elements">4.6 &nbsp;&nbsp; 'BR' elements</A>
  </H3>
  <P>
  The current CSS1 properties and values cannot describe the behavior of the
  'BR' element. In HTML, the 'BR' element specifies a line break between words.
  In effect, the element is replaced by a line break. Future versions of CSS
  may handle added and replaced content, but CSS1-based formatters must treat
  'BR' specially.
  <H2>
    <A NAME="css1-properties">5 &nbsp;&nbsp; CSS1 properties</A>
  </H2>
  <P>
  Style sheets influence the presentation of documents by assigning values
  to style properties. This section lists the defined style properties, and
  their corresponding list of possible values, of CSS1.
  <H3>
    <A NAME="notation-for-property-values">5.1 &nbsp;&nbsp; Notation for property
    values</A>
  </H3>
  <P>
  In the text below, the allowed values for each property are listed with a
  syntax like the following:
  <BLOCKQUOTE>
    <EM>Value:</EM> N | NW | NE<BR>
    <EM>Value:</EM> [ &lt;length&gt; | thick | thin ]{1,4}<BR>
    <EM>Value:</EM> [&lt;family-name&gt; , ]* &lt;family-name&gt;<BR>
    <EM>Value:</EM> &lt;url&gt;? &lt;color&gt; [ / &lt;color&gt; ]?<BR>
    <EM>Value:</EM> &lt;url&gt; || &lt;color&gt;<BR>
  </BLOCKQUOTE>
  <P>
  The words between "&lt;" and "&gt;" give a type of value. The most common
  types are &lt;length&gt;, &lt;percentage&gt;, &lt;url&gt;, &lt;number&gt;
  and &lt;color&gt;; these are described in <A HREF="#units">section 6</A>.
  The more specialized types (e.g. &lt;font-family&gt; and
  &lt;border-style&gt;) are described under the corresponding property.
  <P>
  Other words are keywords that must appear literally, without quotes. The
  slash (/) and the comma (,) must also appear literally.
  <P>
  Several things juxtaposed mean that all of them must occur, in the given
  order. A bar (|) separates alternatives: one of them must occur. A double
  bar (A || B) means that either A or B or both must occur, in any order. Brackets
  ([]) are for grouping. Juxtaposition is stronger than the double bar, and
  the double bar is stronger than the bar. Thus "a b | c || d e" is equivalent
  to "[ a b ] | [ c || [ d e ]]".
  <P>
  Every type, keyword, or bracketed group may be followed by one of the following
  modifiers:
  <UL>
    <LI>
      An asterisk (*) indicates that the preceding type, word or group is repeated
      zero or more times.
    <LI>
      A plus (+) indicates that the preceding type, word or group is repeated one
      or more times.
    <LI>
      A question mark (?) indicates that the preceding type, word or group is optional.
    <LI>
      A pair of numbers in curly braces ({A,B}) indicates that the preceding type,
      word or group is repeated at least A and at most B times.
  </UL>
  <H3>
    <A NAME="font-properties">5.2 &nbsp;&nbsp; Font properties</A>
  </H3>
  <P>
  Setting font properties will be among the most common uses of style sheets.
  Unfortunately, there exists no well-defined and universally accepted taxonomy
  for classifying fonts, and terms that apply to one font family may not be
  appropriate for others. E.g. 'italic' is commonly used to label slanted text,
  but slanted text may also be labeled as being <EM>Oblique, Slanted, Incline,
  Cursive</EM> or <EM>Kursiv</EM>. Therefore it is not a simple problem to
  map typical font selection properties to a specific font.
  <P>
  CSS1 defines the properties <A HREF="#font-family">'font-family'</A>,
  <A HREF="#font-style">'font-style'</A>,
  <A HREF="#font-variant">'font-variant'</A> and
  <A HREF="#font-weight">'font-weight'</A>,
  <A HREF="#font-size">'font-size'</A>, <A HREF="#font">'font'</A>.
  <H4>
    <A NAME="font-matching">5.2.1 &nbsp;&nbsp; Font matching</A>
  </H4>
  <P>
  Because there is no accepted, universal taxonomy of font properties, matching
  of properties to font faces must be done carefully. The properties are matched
  in a well-defined order to insure that the results of this matching process
  are as consistent as possible across UAs (assuming that the same library
  of font faces is presented to each of them).
  <OL>
    <LI>
      The User Agent makes (or accesses) a database of relevant CSS1 properties
      of all the fonts of which the UA is aware. The UA may be aware of a font
      because it has been installed locally or it has been previously downloaded
      over the web. If there are two fonts with exactly the same properties, one
      of them is ignored.
    <LI>
      At a given element and for each character in that element, the UA assembles
      the font-properties applicable to that element. Using the complete set of
      properties, the UA uses the 'font-family' property to choose a tentative
      font family. The remaining properties are tested against the family according
      to the matching criteria described with each property. If there are matches
      for all the remaining properties, then that is the matching font face for
      the given element.
    <LI>
      If there is no matching font face within the 'font-family' being processed
      by step 2, and if there is a next alternative 'font-family' in the font set,
      then repeat step 2 with the next alternative 'font-family'.
    <LI>
      If there is a matching font face, but it doesn't contain a glyph for the
      current character, and if there is a next alternative 'font-family' in the
      font sets, then repeat step 2 with the next alternative 'font-family'. See
      <A HREF="#appendix-c">appendix C</A> for a description of font and character
      encoding.
    <LI>
      If there is no font within the family selected in 2, then use a UA-dependent
      default 'font-family' and repeat step 2, using the best match that can be
      obtained within the default font.
  </OL>
  <P>
  (The above algorithm can be optimized to avoid having to revisit the CSS1
  properties for each character.)
  <P>
  The per-property matching rules from (2) above are as follows:
  <OL>
    <LI>
      <A HREF="#font-style">'font-style'</A> is tried first. 'italic' will be satisfied
      if there is either a face in the UA's font database labeled with the CSS
      keyword 'italic' (preferred) or 'oblique'. Otherwise the values must be matched
      exactly or font-style will fail.
    <LI>
      <A HREF="#font-variant">'font-variant'</A> is tried next. 'normal' matches
      a font not labeled as 'small-caps'; 'small-caps' matches (1) a font labeled
      as 'small-caps', (2) a font in which the small caps are synthesized, or (3)
      a font where all lowercase letters are replaced by upper case letters. A
      small-caps font may be synthesized by electronically scaling uppercase letters
      from a normal font.
    <LI>
      <A HREF="#font-weight">'font-weight'</A> is matched next, it will never fail.
      (See 'font-weight' below.)
    <LI>
      <A HREF="#font-size">'font-size'</A> must be matched within a UA-dependent
      margin of tolerance. (Typically, sizes for scalable fonts are rounded to
      the nearest whole pixel, while the tolerance for bitmapped fonts could be
      as large as 20%.) Further computations, e.g. by 'em' values in other properties,
      are based on the 'font-size' value that is used, not the one that is specified.
  </OL>
  <H4>
    <A NAME="font-family">5.2.2 &nbsp;&nbsp; 'font-family'</A>
  </H4>
  <P>
  <EM>Value:</EM> [[&lt;family-name&gt; | &lt;generic-family&gt;],]*
  [&lt;family-name&gt; | &lt;generic-family&gt;]<BR>
  <EM>Initial:</EM> UA specific<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The value is a prioritized list of font family names and/or generic family
  names. Unlike most other CSS1 properties, values are separated by a comma
  to indicate that they are alternatives:
  <PRE>
  BODY { font-family: gill, helvetica, sans-serif }
</PRE>
  <P>
  There are two types of list values:
  <DL>
    <DT>
      <STRONG>&lt;family-name&gt;</STRONG>
    <DD>
      The name of a font family of choice. In the last example, "gill" and "helvetica"
      are font families.
    <DT>
      <STRONG>&lt;generic-family&gt;</STRONG>
    <DD>
      In the example above, the last value is a generic family name. The following
      generic families are defined:
      <UL>
	<LI>
	  'serif' (e.g. Times)
	<LI>
	  'sans-serif' (e.g. Helvetica)
	<LI>
	  'cursive' (e.g. Zapf-Chancery)
	<LI>
	  'fantasy' (e.g. Western)
	<LI>
	  'monospace' (e.g. Courier)
      </UL>
      <P>
      Style sheet designers are encouraged to offer a generic font family as a
      last alternative.
  </DL>
  <P>
  Font names containing whitespace should be quoted:
  <PRE>
  BODY { font-family: "new century schoolbook", serif }
  
  &lt;BODY STYLE="font-family: 'My own font', fantasy"&gt;
</PRE>
  <P>
  If quoting is omitted, any whitespace characters before and after the font
  name are ignored and any sequence of whitespace characters inside the font
  name is converted to a single space.
  <H4>
    <A NAME="font-style">5.2.3 &nbsp;&nbsp; 'font-style'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | italic | oblique<BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The 'font-style' property selects between normal (sometimes referred to as
  "roman" or "upright"), italic and oblique faces within a font family.
  <P>
  A value of 'normal' selects a font that is classified as 'normal' in the
  UA's font database, while 'oblique' selects a font that is labeled 'oblique'.
  A value of 'italic' selects a font that is labeled 'italic', or, if that
  is not available, one labeled 'oblique'.
  <P>
  The font that is labeled 'oblique' in the UA's font database may actually
  have been generated by electronically slanting a normal font.
  <P>
  Fonts with Oblique, Slanted or Incline in their names will typically be labeled
  'oblique' in the UA's font database. Fonts with <EM>Italic, Cursive</EM>
  or <EM>Kursiv</EM> in their names will typically be labeled 'italic'.
  <PRE>
  H1, H2, H3 { font-style: italic }
  H1 EM { font-style: normal }
</PRE>
  <P>
  In the example above, emphasized text within 'H1' will appear in a normal
  face.
  <H4>
    <A NAME="font-variant">5.2.4 &nbsp;&nbsp; 'font-variant'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | small-caps<BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  Another type of variation within a font family is the small-caps. In a small-caps
  font the lower case letters look similar to the uppercase ones, but in a
  smaller size and with slightly different proportions. The 'font-variant'
  property selects that font.
  <P>
  A value of 'normal' selects a font that is not a small-caps font, 'small-caps'
  selects a small-caps font. It is acceptable (but not required) in CSS1 if
  the small-caps font is a created by taking a normal font and replacing the
  lower case letters by scaled uppercase characters. As a last resort, uppercase
  letters will be used as replacement for a small-caps font.
  <P>
  The following example results in an 'H3' element in small-caps, with emphasized
  words in oblique small-caps:
  <PRE>
  H3 { font-variant: small-caps }
  EM { font-style: oblique }
</PRE>
  <P>
  There may be other variants in the font family as well, such as fonts with
  old-style numerals, small-caps numerals, condensed or expanded letters, etc.
  CSS1 has no properties that select those.
  <P>
  <EM>CSS1 core:</EM> insofar as this property causes text to be transformed
  to uppercase, the same considerations as for
  <A href="#text-transform">'text-transform'</A> apply.
  <H4>
    <A NAME="font-weight">5.2.5 &nbsp;&nbsp; 'font-weight'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | bold | bolder | lighter | 100 | 200 | 300 | 400
  | 500 | 600 | 700 | 800 | 900<BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The 'font-weight' property selects the weight of the font. The values '100'
  to '900' form an ordered sequence, where each number indicates a weight that
  is at least as dark as its predecessor. The keyword 'normal' is synonymous
  with '400', and 'bold' is synonymous with '700'. Keywords other than 'normal'
  and 'bold' have been shown to be often confused with font names and a numerical
  scale was therefore chosen for the 9-value list.
  <PRE>
  P { font-weight: normal }   /* 400 */
  H1 { font-weight: 700 }     /* bold */
</PRE>
  <P>
  The 'bolder' and 'lighter' values select font weights that are relative to
  the weight inherited from the parent:
  <PRE>
  STRONG { font-weight: bolder }
</PRE>
  <P>
  Child elements inherit the resultant weight, not the keyword value.
  <P>
  Fonts (the font data) typically have one or more properties whose values
  are names that are descriptive of the "weight" of a font. There is no accepted,
  universal meaning to these weight names. Their primary role is to distinguish
  faces of differing darkness within a single font family. Usage across font
  families is quite variant; for example a font that you might think of as
  being bold might be described as being <EM>Regular, Roman, Book, Medium,
  Semi-</EM> or <EM>DemiBold, Bold,</EM> or <EM>Black,</EM> depending on how
  black the "normal" face of the font is within the design. Because there is
  no standard usage of names, the weight property values in CSS1 are given
  on a numerical scale in which the value '400' (or 'normal') corresponds to
  the "normal" text face for that family. The weight name associated with that
  face will typically be <EM>Book, Regular, Roman, Normal</EM> or sometimes
  <EM>Medium</EM>.
  <P>
  The association of other weights within a family to the numerical weight
  values is intended only to preserve the ordering of darkness within that
  family. However, the following heuristics tell how the assignment is done
  in typical cases:
  <UL>
    <LI>
      If the font family already uses a numerical scale with nine values (like
      e.g. <EM>OpenType</EM> does), the font weights should be mapped directly.
    <LI>
      If there is both a face labeled <EM>Medium</EM> and one labeled <EM>Book,
      Regular, Roman</EM> or <EM>Normal,</EM> then the <EM>Medium</EM> is normally
      assigned to the '500'.
    <LI>
      The font labeled "Bold" will often correspond to the weight value '700'.
    <LI>
      If there are fewer then 9 weights in the family, the default algorithm for
      filling the "holes" is as follows. If '500' is unassigned, it will be assigned
      the same font as '400'. If any of the values '600', '700', '800' or '900'
      remains unassigned, they are assigned to the same face as the next darker
      assigned keyword, if any, or the next lighter one otherwise. If any of '300',
      '200' or '100' remains unassigned, it is assigned to the next lighter assigned
      keyword, if any, or the next darker otherwise.
  </UL>
  <P>
  The following two examples illustrate the process. Assume four weights in
  the "Example1" family, from lightest to darkest: <EM>Regular, Medium, Bold,
  Heavy.</EM> And assume six weights in the "Example2" family: <EM>Book, Medium,
  Bold, Heavy, Black, ExtraBlack.</EM> Note how in the second example it has
  been decided <EM>not</EM> to assign "Example2 ExtraBlack" to anything.
  <PRE>
    Available faces       |  Assignments  |  Filling the holes
    ----------------------+---------------+-------------------
    "Example1 Regular"    |  400          |  100, 200, 300
    "Example1 Medium"     |  500          |
    "Example1 Bold"       |  700          |  600
    "Example1 Heavy"      |  800          |  900
</PRE>
  <PRE>
    Available faces       |  Assignments  |  Filling the holes
    ----------------------+---------------+-------------------
    "Example2 Book"       |  400          |  100, 200, 300
    "Example2 Medium"     |  500          |
    "Example2 Bold"       |  700          |  600      
    "Example2 Heavy"      |  800          |
    "Example2 Black"      |  900          |
    "Example2 ExtraBlack" |  (none)       |
</PRE>
  <P>
  Since the intent of the relative keywords 'bolder' and 'lighter' is to darken
  or lighten the face <EM>within the family</EM> and because a family may not
  have faces aligned with all the symbolic weight values, the matching of 'bolder'
  is to the next darker face available on the client within the family and
  the matching of 'lighter' is to the next lighter face within the family.
  To be precise, the meaning of the relative keywords 'bolder' and 'lighter'
  is as follows:
  <UL>
    <LI>
      'bolder' selects the next weight that is assigned to a font that is darker
      than the inherited one. If there is no such weight, it simply results in
      the next darker numerical value (and the font remains unchanged), unless
      the inherited value was '900' in which case the resulting weight is also
      '900'.
    <LI>
      'lighter' is similar, but works in the opposite direction: it selects the
      next lighter keyword with a different font from the inherited one, unless
      there is no such font, in which case it selects the next lighter numerical
      value (and keeps the font unchanged).
  </UL>
  <P>
  There is no guarantee that there will be a darker face for each of the
  'font-weight' values; for example, some fonts may have only a normal and
  a bold face, others may have eight different face weights. There is no guarantee
  on how a UA will map font faces within a family to weight values. The only
  guarantee is that a face of a given value will be no less dark than the faces
  of lighter values.
  <H4>
    <A NAME="font-size">5.2.6 &nbsp;&nbsp; 'font-size'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;absolute-size&gt; | &lt;relative-size&gt; |
  &lt;length&gt; | &lt;percentage&gt;<BR>
  <EM>Initial:</EM> medium<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> relative to parent element's font size<BR>
  <DL>
    <DT>
      <B>&lt;absolute-size&gt;</B>
    <DD>
      An &lt;absolute-size&gt; keyword is an index to a table of font sizes computed
      and kept by the UA. Possible values are: [ xx-small | x-small | small | medium
      | large | x-large | xx-large ]. On a computer screen a scaling factor of
      1.5 is suggested between adjacent indexes; if the 'medium' font is 10pt,
      the 'large' font could be 15pt. Different media may need different scaling
      factors. Also, the UA should take the quality and availability of fonts into
      account when computing the table. The table may be different from one font
      family to another.
    <DT>
      <B>&lt;relative-size&gt;</B>
    <DD>
      A &lt;relative-size&gt; keyword is interpreted relative to the table of font
      sizes and the font size of the parent element. Possible values are: [ larger
      | smaller ]. For example, if the parent element has a font size of 'medium',
      a value of 'larger' will make the font size of the current element be 'large'.
      If the parent element's size is not close to a table entry, the UA is free
      to interpolate between table entries or round off to the closest one. The
      UA may have to extrapolate table values if the numerical value goes beyond
      the keywords.
  </DL>
  <P>
  Length and percentage values should not take the font size table into account
  when calculating the font size of the element.
  <P>
  Negative values are not allowed.
  <P>
  On all other properties, 'em' and 'ex' length values refer to the font size
  of the current element. On the 'font-size' property, these length units refer
  to the font size of the parent element.
  <P>
  Note that an application may reinterpret an explicit size, depending on the
  context. E.g., inside a VR scene a font may get a different size because
  of perspective distortion.
  <P>
  Examples:
  <PRE>
  P { font-size: 12pt; }
  BLOCKQUOTE { font-size: larger }
  EM { font-size: 150% }
  EM { font-size: 1.5em }
</PRE>
  <P>
  If the suggested scaling factor of 1.5 is used, the last three declarations
  are identical.
  <H4>
    <A NAME="font">5.2.7 &nbsp;&nbsp; 'font'</A>
  </H4>
  <P>
  <EM>Value:</EM> [ &lt;font-style&gt; || &lt;font-variant&gt; ||
  &lt;font-weight&gt; ]? &lt;font-size&gt; [ / &lt;line-height&gt; ]?
  &lt;font-family&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> allowed on &lt;font-size&gt; and
  &lt;line-height&gt;<BR>
  <P>
  The 'font' property is a shorthand property for setting
  <A HREF="#font-style">'font-style'</A>
  <A HREF="#font-variant">'font-variant'</A>
  <A HREF="#font-weight">'font-weight'</A>
  <A HREF="#font-size">'font-size'</A>,
  <A HREF="#line-height">'line-height'</A> and
  <A HREF="#font-family">'font-family'</A> at the same place in the style sheet.
  The syntax of this property is based on a traditional typographical shorthand
  notation to set multiple properties related to fonts.
  <P>
  For a definition of allowed and initial values, see the previously defined
  properties. Properties for which no values are given are set to their initial
  value.
  <PRE>
  P { font: 12pt/14pt sans-serif }
  P { font: 80% sans-serif }
  P { font: x-large/110% "new century schoolbook", serif }
  P { font: bold italic large Palatino, serif }
  P { font: normal small-caps 120%/120% fantasy }
</PRE>
  <P>
  In the second rule, the font size percentage value ('80%') refers to the
  font size of the parent element. In the third rule, the line height percentage
  refers to the font size of the element itself.
  <P>
  In the first three rules above, the 'font-style', 'font-variant' and
  'font-weight' are not explicitly mentioned, which means they are all three
  set to their initial value ('normal'). The fourth rule sets the 'font-weight'
  to 'bold', the 'font-style' to 'italic' and implicitly sets 'font-variant'
  to 'normal'.
  <P>
  The fifth rule sets the 'font-variant' ('small-caps'), the 'font-size' (120%
  of the parent's font), the 'line-height' (120% times the font size) and the
  'font-family' ('fantasy'). It follows that the keyword 'normal' applies to
  the two remaining properties: 'font-style' and 'font-weight'.
  <H3>
    <A NAME="color-and-background-properties">5.3 &nbsp;&nbsp; Color and background
    properties</A>
  </H3>
  <P>
  These properties describe the color (often called <EM>foreground color</EM>)
  and background of an element (i.e. the surface onto which the content is
  rendered). One can set a background color and/or a background image. The
  position of the image, if/how it is repeated, and whether it is fixed or
  scrolled relative to the canvas can also be set.
  <P>
  The 'color' property inherits normally. The background properties do not
  inherit, but the parent element's background will shine through by default
  because of the initial 'transparent' value on 'background-color'.
  <H4>
    <A NAME="color">5.3.1 &nbsp;&nbsp; 'color'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;color&gt;<BR>
  <EM>Initial:</EM> UA specific<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property describes the text color of an element (often referred to as
  the <EM>foreground</EM> color). There are different ways to specify red:
  <PRE>
  EM { color: red }              /* natural language */
  EM { color: rgb(255,0,0) }     /* RGB range 0-255   */
</PRE>
  <P>
  See <A HREF="#color-units">section 6.3</A> for a description of possible
  color values.
  <H4>
    <A NAME="background-color">5.3.2 &nbsp;&nbsp; 'background-color'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;color&gt; | transparent<BR>
  <EM>Initial:</EM> transparent<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the background color of an element.
  <PRE>
  H1 { background-color: #F00 }
</PRE>
  <H4>
    <A NAME="background-image">5.3.3 &nbsp;&nbsp; 'background-image'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;url&gt; | none<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the background image of an element. When setting a background
  image, one should also set a background color that will be used when the
  image is unavailable. When the image is available, it is overlaid on top
  of the background color.
  <PRE>
  BODY { background-image: url(marble.gif) }
  P { background-image: none }
</PRE>
  <H4>
    <A NAME="background-repeat">5.3.4 &nbsp;&nbsp; 'background-repeat'</A>
  </H4>
  <P>
  <EM>Value:</EM> repeat | repeat-x | repeat-y | no-repeat<BR>
  <EM>Initial:</EM> repeat<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  If a background image is specified, the value of 'background-repeat' determines
  how/if the image is repeated.
  <P>
  A value of 'repeat' means that the image is repeated both horizontally and
  vertically. The 'repeat-x' ('repeat-y') value makes the image repeat horizontally
  (vertically), to create a single band of images from one side to the other.
  With a value of 'no-repeat', the image is not repeated.
  <PRE>
  BODY { 
    background: red url(pendant.gif);
    background-repeat: repeat-y;
  }
</PRE>
  <P>
  In the example above, the image will only be repeated vertically.
  <H4>
    <A NAME="background-attachment">5.3.5 &nbsp;&nbsp; 'background-attachment'</A>
  </H4>
  <P>
  <EM>Value:</EM> scroll | fixed<BR>
  <EM>Initial:</EM> scroll<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  If a background image is specified, the value of 'background-attachment'
  determines if it is fixed with regard to the canvas or if it scrolls along
  with the content.
  <PRE>
  BODY { 
    background: red url(pendant.gif);
    background-repeat: repeat-y;
    background-attachment: fixed;
  }
</PRE>
  <P>
  <EM>CSS1 core:</EM> UAs may treat 'fixed' as 'scroll'. However, it is recommended
  they interpret 'fixed' correctly, at least on the HTML and BODY elements,
  since there is no way for an author to provide an image only for those browsers
  that support 'fixed'. (See <A href="#css1-conformance">section 7</A>.)
  <H4>
    <A NAME="background-position">5.3.6 &nbsp;&nbsp; 'background-position'</A>
  </H4>
  <P>
  <EM>Value:</EM> [&lt;percentage&gt; | &lt;length&gt;]{1,2} | [top | center
  | bottom] || [left | center | right]<BR>
  <EM>Initial:</EM> 0% 0%<BR>
  <EM>Applies to:</EM> block-level and replaced elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to the size of the element itself<BR>
  <P>
  If a background image has been specified, the value of 'background-position'
  specifies its initial position.
  <P>
  With a value pair of '0% 0%', the upper left corner of the image is placed
  in the upper left corner of the box that surrounds the content of the element
  (i.e., not the box that surrounds the padding, border or margin). A value
  pair of '100% 100%' places the lower right corner of the image in the lower
  right corner of the element. With a value pair of '14% 84%', the point 14%
  across and 84% down the image is to be placed at the point 14% across and
  84% down the element.
  <P>
  With a value pair of '2cm 2cm', the upper left corner of the image is placed
  2cm to the right and 2cm below the upper left corner of the element.
  <P>
  If only one percentage or length value is given, it sets the horizontal position
  only, the vertical position will be 50%. If two values are given, the horizontal
  position comes first. Combinations of length and percentage values are allowed,
  e.g. '50% 2cm'. Negative positions are allowed.
  <P>
  One can also use keyword values to indicate the position of the background
  image. Keywords cannot be combined with percentage values, or length values.
  The possible combinations of keywords and their interpretations are as follows:
  <UL>
    <LI>
      'top left' and 'left top' both mean the same as '0% 0%'.
    <LI>
      'top', 'top center' and 'center top' mean the same as '50% 0%'.
    <LI>
      'right top' and 'top right' mean the same as '100% 0%'.
    <LI>
      'left', 'left center' and 'center left' mean the same as '0% 50%'.
    <LI>
      'center' and 'center center' mean the same as '50% 50%'.
    <LI>
      'right', 'right center' and 'center right' mean the same as '100% 50%'.
    <LI>
      'bottom left' and 'left bottom' mean the same as '0% 100%'.
    <LI>
      'bottom', 'bottom center' and 'center bottom' mean the same as '50% 100%'.
    <LI>
      'bottom right' and 'right bottom' mean the same as '100% 100%'.
  </UL>
  <P>
  examples:
  <PRE>
  BODY { background: url(banner.jpeg) right top }    /* 100%   0% */
  BODY { background: url(banner.jpeg) top center }   /*  50%   0% */
  BODY { background: url(banner.jpeg) center }       /*  50%  50% */
  BODY { background: url(banner.jpeg) bottom }       /*  50% 100% */
</PRE>
  <P>
  If the background image is fixed with regard to the canvas (see the
  'background-attachment' property above), the image is placed relative to
  the canvas instead of the element. E.g.:
  <PRE>
  BODY { 
    background-image: url(logo.png);
    background-attachment: fixed;
    background-position: 100% 100%;
  } 
</PRE>
  <P>
  In the example above, the image is placed in the lower right corner of the
  canvas.
  <H4>
    <A NAME="background">5.3.7 &nbsp;&nbsp; 'background'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;background-color&gt; || &lt;background-image&gt; ||
  &lt;background-repeat&gt; || &lt;background-attachment&gt; ||
  &lt;background-position&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> allowed on &lt;background-position&gt;<BR>
  <P>
  The 'background' property is a shorthand property for setting the individual
  background properties (i.e., 'background-color', 'background-image',
  'background-repeat', 'background-attachment' and 'background-position') at
  the same place in the style sheet.
  <P>
  Possible values on the 'background' properties are the set of all possible
  values on the individual properties.
  <PRE>
  BODY { background: red }
  P { background: url(chess.png) gray 50% repeat fixed }
</PRE>
  <P>
  The 'background' property always sets all the individual background properties.
  In the first rule of the above example, only a value for 'background-color'
  has been given and the other individual properties are set to their initial
  value. In the second rule, all individual properties have been specified.
  <H3>
    <A NAME="text-properties">5.4 &nbsp;&nbsp; Text properties</A>
  </H3>
  <H4>
    <A NAME="word-spacing">5.4.1 &nbsp;&nbsp; 'word-spacing'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | &lt;length&gt; <BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The length unit indicates an addition to the default space between words.
  Values can be negative, but there may be implementation-specific limits.
  The UA is free to select the exact spacing algorithm. The word spacing may
  also be influenced by justification (which is a value of the 'align' property).
  <PRE>
  H1 { word-spacing: 0.4em }
</PRE>
  <P>
  Here, the word-spacing between each word in 'H1' elements would be increased
  by '1em'.
  <P>
  <EM>CSS1 core:</EM> UAs may interpret any value of 'word-spacing' as 'normal'.
  (See <A href="#css1-conformance">section 7</A>.)
  <H4>
    <A NAME="letter-spacing">5.4.2 &nbsp;&nbsp; 'letter-spacing'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | &lt;length&gt; <BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The length unit indicates an addition to the default space between characters.
  Values can be negative, but there may be implementation-specific limits.
  The UA is free to select the exact spacing algorithm. The letter spacing
  may also be influenced by justification (which is a value of the 'align'
  property).
  <PRE>
  BLOCKQUOTE { letter-spacing: 0.1em }
</PRE>
  <P>
  Here, the letter-spacing between each character in 'BLOCKQUOTE' elements
  would be increased by '0.1em'.
  <P>
  With a value of 'normal', the UAs may change the space between letters to
  justify text. This will not happen if 'letter-spacing' is explicitly set
  to a &lt;length&gt; value:
  <PRE>
  BLOCKQUOTE { letter-spacing: 0 }
  BLOCKQUOTE { letter-spacing: 0cm }
</PRE>
  <P>
  When the resultant space between two letters is not the same as the default
  space, UAs should not use ligatures.
  <P>
  <EM>CSS1 core:</EM> UAs may interpret any value of 'letter-spacing' as 'normal'.
  (See <A href="#css1-conformance">section 7</A>.)
  <H4>
    <A NAME="text-decoration">5.4.3 &nbsp;&nbsp; 'text-decoration'</A>
  </H4>
  <P>
  <EM>Value:</EM> none | [ underline || overline || line-through || blink ]<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no, but see clarification below<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property describes decorations that are added to the text of an element.
  If the element has no text (e.g. the 'IMG' element in HTML) or is an empty
  element (e.g. '&lt;EM&gt;&lt;/EM&gt;'), this property has no effect. A value
  of 'blink' causes the text to blink.
  <P>
  The color(s) required for the text decoration should be derived from the
  'color' property value.
  <P>
  This property is not inherited, but elements should match their parent. E.g.,
  if an element is underlined, the line should span the child elements. The
  color of the underlining will remain the same even if descendant elements
  have different 'color' values.
  <PRE>
  A:link, A:visited, A:active { text-decoration: underline }
</PRE>
  <P>
  The example above would underline the text of all links (i.e., all 'A' elements
  with a 'HREF' attribute).
  <P>
  UAs must recognize the keyword 'blink', but are not required to support the
  blink effect.
  <H4>
    <A NAME="vertical-align">5.4.4 &nbsp;&nbsp; 'vertical-align'</A>
  </H4>
  <P>
  <EM>Value:</EM> baseline | sub | super | top | text-top | middle | bottom
  | text-bottom | &lt;percentage&gt; <BR>
  <EM>Initial:</EM> baseline<BR>
  <EM>Applies to:</EM> inline elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to the 'line-height' of the element
  itself<BR>
  <P>
  The property affects the vertical positioning of the element. One set of
  keywords is relative to the parent element:
  <DL>
    <DT>
      'baseline'
    <DD>
      align the baseline of the element (or the bottom, if the element doesn't
      have a baseline) with the baseline of the parent
    <DT>
      'middle'
    <DD>
      align the vertical midpoint of the element (typically an image) with the
      baseline plus half the x-height of the parent
    <DT>
      'sub'
    <DD>
      subscript the element
    <DT>
      'super'
    <DD>
      superscript the element
    <DT>
      'text-top'
    <DD>
      align the top of the element with the top of the parent element's font
    <DT>
      'text-bottom'
    <DD>
      align the bottom of the element with the bottom of the parent element's font
  </DL>
  <P>
  Another set of properties are relative to the formatted line that the element
  is a part of:
  <DL>
    <DT>
      'top'
    <DD>
      align the top of the element with the tallest element on the line
    <DT>
      'bottom'
    <DD>
      align the bottom of the element with the lowest element on the line
  </DL>
  <P>
  Using the 'top' and 'bottom' alignment, unsolvable situations can occur where
  element dependencies form a loop.
  <P>
  Percentage values refer to the value of the 'line-height' property of the
  element itself. They raise the baseline of the element (or the bottom, if
  it has no baseline) the specified amount above the baseline of the parent.
  Negative values are possible. E.g., a value of '-100%' will lower the element
  so that the baseline of the element ends up where the baseline of the next
  line should have been. This allows precise control over the vertical position
  of elements (such as images that are used in place of letters) that don't
  have a baseline.
  <P>
  It is expected that a future version of CSS will allow &lt;length&amp;t;
  as a value on this property.
  <H4>
    <A NAME="text-transform">5.4.5 &nbsp;&nbsp; 'text-transform'</A>
  </H4>
  <P>
  <EM>Value:</EM> capitalize | uppercase | lowercase | none<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <DL>
    <DT>
      'capitalize'
    <DD>
      uppercases the first character of each word
    <DT>
      'uppercase'
    <DD>
      uppercases all letters of the element
    <DT>
      'lowercase'
    <DD>
      lowercases all letters of the element
    <DT>
      'none'
    <DD>
      neutralizes inherited value.
  </DL>
  <P>
  The actual transformation in each case is human language dependent. See
  <A href="#ref4">[4]</A> for ways to find the language of an element.
  <PRE>
  H1 { text-transform: uppercase }
</PRE>
  <P>
  The example above would put 'H1' elements in uppercase text.
  <P>
  <EM>CSS1 core:</EM> UAs may ignore 'text-transform' (i.e., treat it as 'none')
  for characters that are not from the Latin-1 repertoire and for elements
  in languages for which the transformation is different from that specified
  by the case-conversion tables of Unicode [8].
  <H4>
    <A NAME="text-align">5.4.6 &nbsp;&nbsp; 'text-align'</A>
  </H4>
  <P>
  <EM>Value:</EM> left | right | center | justify<BR>
  <EM>Initial:</EM> UA specific<BR>
  <EM>Applies to:</EM> block-level elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property describes how text is aligned within the element. The actual
  justification algorithm used is UA and human language dependent.
  <P>
  Example:
  <PRE>
  DIV.center { text-align: center }
</PRE>
  <P>
  Since 'text-align' inherits, all block-level elements inside the 'DIV' element
  with 'CLASS=center' will be centered. Note that alignments are relative to
  the width of the element, not the canvas. If 'justify' is not supported,
  the UA will supply a replacement. Typically, this will be 'left' for western
  languages.
  <P>
  <EM>CSS1 core:</EM> UAs may treat 'justify' as 'left' or 'right', depending
  on whether the element's default writing direction is left-to-right or
  right-to-left, respectively.
  <H4>
    <A NAME="text-indent">5.4.7 &nbsp;&nbsp; 'text-indent'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt;<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> block-level elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  The property specifies the indentation that appears before the first formatted
  line. The value of 'text-indent' may be negative, but there may be
  implementation-specific limits. An indentation is not inserted in the middle
  of an element that was broken by another (such as 'BR' in HTML).
  <P>
  Example:
  <PRE>
  P { text-indent: 3em }
</PRE>
  <H4>
    <A NAME="line-height">5.4.8 &nbsp;&nbsp; 'line-height'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | &lt;number&gt; | &lt;length&gt; |
  &lt;percentage&gt;<BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> relative to the font size of the element itself<BR>
  <P>
  The property sets the distance between two adjacent lines' baselines.
  <P>
  When a numerical value is specified, the line height is given by the font
  size of the current element multiplied with the numerical value. This differs
  from a percentage value in the way it inherits: when a numerical value is
  specified, child elements will inherit the factor itself, not the resultant
  value (as is the case with <A HREF="#percentage-units">percentage</A> and
  other units).
  <P>
  Negative values are not allowed.
  <P>
  The three rules in the example below have the same resultant line height:
  <PRE>
  DIV { line-height: 1.2; font-size: 10pt }     /* number */
  DIV { line-height: 1.2em; font-size: 10pt }   /* length */
  DIV { line-height: 120%; font-size: 10pt }    /* percentage */
</PRE>
  <P>
  A value of 'normal' sets the 'line-height' to a reasonable value for the
  element's font. It is suggested that UAs set the 'normal' value to be a number
  in the range of 1.0 to 1.2.
  <P>
  See the <A HREF="#the-height-of-lines">section 4.7</A> for a description
  on how 'line-height' influences the formatting of a block-level element.
  <H3>
    <A NAME="box-properties">5.5 &nbsp;&nbsp; Box properties</A>
  </H3>
  <P>
  The box properties set the size, circumference and position of the boxes
  that represent elements. See the <A HREF="#formatting-model">formatting model
  (section 4)</A> for examples on how to use the box properties.
  <P>
  The margin properties properties set the margin of an element. The 'margin'
  property sets the border for all four sides while the other margin properties
  only set their respective side.
  <P>
  The padding properties describe how much space to insert between the border
  and the content (e.g., text or image). The 'padding' property sets the padding
  for all four sides while the other padding properties only set their respective
  side.
  <P>
  The border properties set the borders of an element. Each element has four
  borders, one on each side, that are defined by their width, color and style.
  <P>
  The 'width' and 'height' properties set the size of the box, and the 'float'
  and 'clear' properties can alter the position of elements.
  <H4>
    <A NAME="margin-top">5.5.1 &nbsp;&nbsp; 'margin-top'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt; | auto<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the top margin of an element:
  <PRE>
  H1 { margin-top: 2em }
</PRE>
  <P>
  A negative value is allowed, but there may be implementation-specific limits.
  <H4>
    <A NAME="margin-right">5.5.2 &nbsp;&nbsp; 'margin-right'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt; | auto<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the right margin of an element:
  <PRE>
  H1 { margin-right: 12.3% }
</PRE>
  <P>
  A negative value is allowed, but there may be implementation-specific limits.
  <H4>
    <A NAME="margin-bottom">5.5.3 &nbsp;&nbsp; 'margin-bottom'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt; | auto<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the bottom margin of an element:
  <PRE>
  H1 { margin-bottom: 3px }
</PRE>
  <P>
  A negative value is allowed, but there may be implementation-specific limits.
  <H4>
    <A NAME="margin-left">5.5.4 &nbsp;&nbsp; 'margin-left'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt; | auto<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the left margin of an element:
  <PRE>
  H1 { margin-left: 2em }
</PRE>
  <P>
  A negative value is allowed, but there may be implementation-specific limits.
  <H4>
    <A NAME="margin">5.5.5 &nbsp;&nbsp; 'margin'</A>
  </H4>
  <P>
  <EM>Value:</EM> [ &lt;length&gt; | &lt;percentage&gt; | auto ]{1,4} <BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  The 'margin' property is a shorthand property for setting 'margin-top',
  'margin-right' 'margin-bottom' and 'margin-left' at the same place in the
  style sheet.
  <P>
  If four length values are specified they apply to top, right, bottom and
  left respectively. If there is only one value, it applies to all sides, if
  there are two or three, the missing values are taken from the opposite side.
  <PRE>
  BODY { margin: 2em } /* all margins set to 2em */
  BODY { margin: 1em 2em } /* top &amp; bottom = 1em, right &amp; left = 2em */
  BODY { margin: 1em 2em 3em } /* top=1em, right=2em, bottom=3em, left=2em */
</PRE>
  <P>
  The last rule of the example above is equivalent to the example below:
  <PRE>
  BODY {
    margin-top: 1em;
    margin-right: 2em;
    margin-bottom: 3em;
    margin-left: 2em;        /* copied from opposite side (right) */
  }
</PRE>
  <P>
  Negative margin values are allowed, but there may be implementation-specific
  limits.
  <H4>
    <A NAME="padding-top">5.5.6 &nbsp;&nbsp; 'padding-top'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt;<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the top padding of an element.
  <PRE>
  BLOCKQUOTE { padding-top: 0.3em }
</PRE>
  <P>
  Padding values cannot be negative.
  <H4>
    <A NAME="padding-right">5.5.7 &nbsp;&nbsp; 'padding-right'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt;<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the right padding of an element.
  <PRE>
  BLOCKQUOTE { padding-right: 10px }
</PRE>
  <P>
  Padding values cannot be negative.
  <H4>
    <A NAME="padding-bottom">5.5.8 &nbsp;&nbsp; 'padding-bottom'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt;<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the bottom padding of an element.
  <PRE>
  BLOCKQUOTE { padding-bottom: 2em }
</PRE>
  <P>
  Padding values cannot be negative.
  <H4>
    <A NAME="padding-left">5.5.9 &nbsp;&nbsp; 'padding-left'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt;<BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property sets the left padding of an element.
  <PRE>
  BLOCKQUOTE { padding-left: 20% }
</PRE>
  <P>
  Padding values cannot be negative.
  <H4>
    <A NAME="padding">5.5.10 &nbsp;&nbsp; 'padding'</A>
  </H4>
  <P>
  <EM>Value:</EM> [ &lt;length&gt; | &lt;percentage&gt; ]{1,4} <BR>
  <EM>Initial:</EM> 0<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  The 'padding' property is a shorthand property for setting 'padding-top',
  'padding-right' 'padding-bottom' and 'padding-left' at the same place in
  the style sheet.
  <P>
  If four values are specified they apply to top, right, bottom and left
  respectively. If there is only one value, it applies to all sides, if there
  are two or three, the missing values are taken from the opposite side.
  <P>
  The surface of the padding area is set with the 'background' property:
  <PRE>
  H1 { 
    background: white; 
    padding: 1em 2em;
  } 
</PRE>
  <P>
  The example above sets a '1em' padding vertically ('padding-top' and
  'padding-bottom') and a '2em' padding horizontally ('padding-right' and
  'padding-left'). The 'em' unit is relative to the element's font size: '1em'
  is equal to the size of the font in use.
  <P>
  Padding values cannot be negative.
  <H4>
    <A NAME="border-top-width">5.5.11 &nbsp;&nbsp; 'border-top-width'</A>
  </H4>
  <P>
  <EM>Value:</EM> thin | medium | thick | &lt;length&gt;<BR>
  <EM>Initial:</EM> 'medium'<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the width of an element's top border. The width of the
  keyword values are UA dependent, but the following holds: 'thin' &lt;= 'medium'
  &lt;= 'thick'.
  <P>
  The keyword widths are constant throughout a document:
  <PRE>
  H1 { border: solid thick red }
  P  { border: solid thick blue }
</PRE>
  <P>
  In the example above, 'H1' and 'P' elements will have the same border width
  regardless of font size. To achieve relative widths, the 'em' unit can be
  used:
  <PRE>
  H1 { border: solid 0.5em }
</PRE>
  <P>
  Border widths cannot be negative.
  <H4>
    <A NAME="border-right-width">5.5.12 &nbsp;&nbsp; 'border-right-width'</A>
  </H4>
  <P>
  <EM>Value:</EM> thin | medium | thick | &lt;length&gt;<BR>
  <EM>Initial:</EM> 'medium'<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the width of an element's right border. Otherwise it is
  equivalent to the <A HREF="#border-top-width">'border-top-width'</A>.
  <H4>
    <A NAME="border-bottom-width">5.5.13 &nbsp;&nbsp; 'border-bottom-width'</A>
  </H4>
  <P>
  <EM>Value:</EM> thin | medium | thick | &lt;length&gt;<BR>
  <EM>Initial:</EM> 'medium'<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the width of an element's bottom border. Otherwise it
  is equivalent to the <A HREF="#border-top-width">'border-top-width'</A>.
  <H4>
    <A NAME="border-left-width">5.5.14 &nbsp;&nbsp; 'border-left-width'</A>
  </H4>
  <P>
  <EM>Value:</EM> thin | medium | thick | &lt;length&gt;<BR>
  <EM>Initial:</EM> 'medium'<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the width of an element's left border. Otherwise it is
  equivalent to the <A HREF="#border-top-width">'border-top-width'</A>.
  <H4>
    <A NAME="border-width">5.5.15 &nbsp;&nbsp; 'border-width'</A>
  </H4>
  <P>
  <EM>Value:</EM> [thin | medium | thick | &lt;length&gt;]{1,4}<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property is a shorthand property for setting 'border-width-top',
  'border-width-right', 'border-width-bottom' and 'border-width-left' at the
  same place in the style sheet.
  <P>
  There can be from one to four values, with the following interpretation:
  <UL>
    <LI>
      one value: all four border widths are set to that value
    <LI>
      two values: top and bottom border widths are set to the first value, right
      and left are set to the second
    <LI>
      three values: top is set to the first, right and left are set to the second,
      bottom is set to the third
    <LI>
      four values: top, right, bottom and left, respectively
  </UL>
  <P>
  In the examples below, the comments indicate the resulting widths of the
  top, right, bottom and left borders:
  <PRE>
  H1 { border-width: thin }                   /* thin thin thin thin */
  H1 { border-width: thin thick }             /* thin thick thin thick */
  H1 { border-width: thin thick medium }      /* thin thick medium thin */
  H1 { border-width: thin thick medium none } /* thin thick medium none */
</PRE>
  <P>
  Border widths cannot be negative.
  <H4>
    <A NAME="border-color">5.5.16 &nbsp;&nbsp; 'border-color'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;color&gt;{1,4}<BR>
  <EM>Initial:</EM> the value of the 'color' property<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The 'border-color' property sets the color of the four borders. 'border-color'
  can have from one to four values, and the values are set on the different
  sides as for 'border-width' above.
  <P>
  If no color value is specified, the value of the 'color' property of the
  element itself will take its place:
  <PRE>
  P { 
    color: black; 
    background: white; 
    border: solid;
  }
</PRE>
  <P>
  In the above example, the border will be a solid black line.
  <H4>
    <A NAME="border-style">5.5.17 &nbsp;&nbsp; 'border-style'</A>
  </H4>
  <P>
  <EM>Value:</EM> none | dotted | dashed | solid | double | groove | ridge
  | inset | outset<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The 'border-style' property sets the style of the four borders. It can have
  from one to four values, and the values are set on the different sides as
  for 'border-width' above.
  <PRE>
  #xy34 { border-style: solid dotted }
</PRE>
  <P>
  In the above example, the horizontal borders will be 'solid' and the vertical
  borders will be 'dotted'.
  <P>
  Since the initial value of the border styles is 'none', no borders will be
  visible unless the border style is set.
  <P>
  The border styles mean:
  <DL>
    <DT>
      none
    <DD>
      no border is drawn (regardless of the 'border-width' value)
    <DT>
      dotted
    <DD>
      the border is a dotted line drawn on top of the background of the element
    <DT>
      dashed
    <DD>
      the border is a dashed line drawn on top of the background of the element
    <DT>
      solid
    <DD>
      the border is a solid line
    <DT>
      double
    <DD>
      the border is a double line drawn on top of the background of the element.
      The sum of the two single lines and the space between equals the
      &lt;border-width&gt; value.
    <DT>
      groove
    <DD>
      a 3D groove is drawn in colors based on the &lt;color&gt; value.
    <DT>
      ridge
    <DD>
      a 3D ridge is drawn in colors based on the &lt;color&gt; value.
    <DT>
      inset
    <DD>
      a 3D inset is drawn in colors based on the &lt;color&gt; value.
    <DT>
      outset
    <DD>
      a 3D outset is drawn in colors based on the &lt;color&gt; value.
  </DL>
  <P>
  <EM>CSS1 core:</EM> UAs may interpret all of 'dotted', 'dashed', 'double',
  'groove', 'ridge', 'inset' and 'outset' as 'solid'.
  <H4>
    <A NAME="border-top">5.5.18 &nbsp;&nbsp; 'border-top'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;border-top-width&gt; || &lt;border-style&gt; ||
  &lt;color&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This is a shorthand property for setting the width, style and color of an
  element's top border.
  <PRE>
  H1 { border-bottom: thick solid red }
</PRE>
  <P>
  The above rule will set the width, style and color of the border below the
  H1 element. Omitted values will be set to their initial values:
  <PRE>
  H1 { border-bottom: thick solid }
</PRE>
  <P>
  Since the color value is omitted in the example above, the border color will
  be the same as the 'color' value of the element itself.
  <P>
  Note that while the 'border-style' property accepts up to four values, this
  property only accepts one style value.
  <H4>
    <A NAME="border-right">5.5.19 &nbsp;&nbsp; 'border-right'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;border-right-width&gt; || &lt;border-style&gt; ||
  &lt;color&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This is a shorthand property for setting the width, style and color of an
  element's right border. Otherwise it is equivalent to the
  <A HREF="#border-top">'border-top'</A>.
  <H4>
    <A NAME="border-bottom">5.5.20 &nbsp;&nbsp; 'border-bottom'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;border-bottom-width&gt; || &lt;border-style&gt; ||
  &lt;color&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This is a shorthand property for setting the width, style and color of an
  element's bottom border. Otherwise it is equivalent to the
  <A HREF="#border-top">'border-top'</A>.
  <H4>
    <A NAME="border-left">5.5.21 &nbsp;&nbsp; 'border-left'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;border-left-width&gt; || &lt;border-style&gt; ||
  &lt;color&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This is a shorthand property for setting the width, style and color of an
  element's left border. Otherwise it is equivalent to the
  <A HREF="#border-top">'border-top'</A>.
  <H4>
    <A NAME="border">5.5.22 &nbsp;&nbsp; 'border'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;border-width&gt; || &lt;border-style&gt; ||
  &lt;color&gt; <BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The 'border' property is a shorthand property for setting the same width,
  color and style on all four borders of an element. For example, the first
  rule below is equivalent to the set of four rules shown after it:
  <PRE>
  P { border: solid red }
  P {
    border-top: solid red;
    border-right: solid red;
    border-bottom: solid red;
    border-left: solid red
  }
</PRE>
  <P>
  Unlike the shorthand 'margin' and 'padding' properties, the 'border' property
  cannot set different values on the four borders. To do so, one or more of
  the other border properties must be used.
  <P>
  Since the properties to some extent have overlapping functionality, the order
  in which the rules are specified becomes important. Consider this example:
  <PRE>
  BLOCKQUOTE {
    border-color: red;
    border-left: double
    color: black;
  }
</PRE>
  <P>
  In the above example, the color of the left border will be black, while the
  other borders are red. This is due to 'border-left' setting the width, style
  and color. Since the color value is not specified on the 'border-left' property,
  it will be taken from the 'color' property. The fact that the 'color' property
  is set after the 'border-left' property is not relevant.
  <P>
  Note that while the 'border-width' property accepts up to four length values,
  this property only accepts one.
  <H4>
    <A NAME="width">5.5.23 &nbsp;&nbsp; 'width'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | &lt;percentage&gt; | auto <BR>
  <EM>Initial:</EM> auto<BR>
  <EM>Applies to:</EM> block-level and replaced elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> refer to parent element's width<BR>
  <P>
  This property can be applied to text elements, but it is most useful with
  replaced elements such as images. The width is to be enforced by scaling
  the image if necessary. When scaling, the aspect ratio of the image is preserved
  if the 'height' property is 'auto'.
  <P>
  Example:
  <PRE>
  IMG.icon { width: 100px }
</PRE>
  <P>
  If the 'width' and 'height' of a replaced element are both 'auto', these
  properties will be set to the intrinsic dimensions of the element.
  <P>
  Negative values are not allowed.
  <P>
  See the <A HREF="#formatting-model">formatting model (section 4)</A> for
  a description of the relationship between this property and the margin and
  padding.
  <H4>
    <A NAME="height">5.5.24 &nbsp;&nbsp; 'height'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;length&gt; | auto <BR>
  <EM>Initial:</EM> auto<BR>
  <EM>Applies to:</EM> block-level and replaced elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property can be applied to text, but it is most useful with replaced
  elements such as images. The height is to be enforced by scaling the image
  if necessary. When scaling, the aspect ratio of the image is preserved if
  the 'width' property is 'auto'.
  <P>
  Example:
  <PRE>
  IMG.icon { height: 100px }
</PRE>
  <P>
  If the 'width' and 'height' of a replaced element are both 'auto', these
  properties will be set to the intrinsic dimensions of the element.
  <P>
  If applied to a textual element, the height can be enforced with e.g. a
  scrollbar.
  <P>
  Negative values are not allowed.
  <P>
  <EM>CSS1 core:</EM> UAs may ignore the 'height' property (i.e., treat it
  as 'auto') if the element is not a replaced element.
  <H4>
    <A NAME="float">5.5.25 &nbsp;&nbsp; 'float'</A>
  </H4>
  <P>
  <EM>Value:</EM> left | right | none<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  With the value 'none', the element will be displayed where it appears in
  the text. With a value of 'left' ('right') the element will be moved to the
  left ('right') and the text will wrap on the right (left) side of the element.
  With a value of 'left' or 'right', the element is treated as block-level
  (i.e. the 'display' property is ignored). See
  <A href="#floating-elements">section 4.1.4</A> for a full specification.
  <PRE>
  IMG.icon { 
    float: left;
    margin-left: 0;
  }
</PRE>
  <P>
  The above example will place all IMG elements with 'CLASS=icon' along the
  left side of the parent element.
  <P>
  This property is most often used with inline images, but also applies to
  text elements.
  <H4>
    <A NAME="clear">5.5.26 &nbsp;&nbsp; 'clear'</A>
  </H4>
  <P>
  <EM>Value:</EM> none | left | right | both<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property specifies if an element allows floating elements on its sides.
  More specifically, the value of this property lists the sides where floating
  elements are not accepted. With 'clear' set to 'left', an element will be
  moved below any floating element on the left side. With 'clear' set to 'none',
  floating elements are allowed on all sides. Example:
  <PRE>
  H1 { clear: left }
</PRE>
  <H3>
    <A NAME="classification-properties">5.6 &nbsp;&nbsp; Classification
    properties</A>
  </H3>
  <P>
  These properties classify elements into categories more than they set specific
  visual parameters.
  <P>
  The list-style properties describe how list items (i.e. elements with a 'display'
  value of 'list-item') are formatted. The list-style properties can be set
  on any element, and it will inherit normally down the tree. However, they
  will only be have effect on elements with a 'display' value of 'list-item'.
  In HTML this is typically the case for the 'LI' element.
  <H4>
    <A NAME="display">5.6.1 &nbsp;&nbsp; 'display'</A>
  </H4>
  <P>
  <EM>Value:</EM> block | inline | list-item | none<BR>
  <EM>Initial:</EM> block<BR>
  <EM>Applies to:</EM> all elements<BR>
  <EM>Inherited:</EM> no<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property describes how/if an element is displayed on the canvas (which
  may be on a printed page, a computer display etc.).
  <P>
  An element with a 'display' value of 'block' opens a new box. The box is
  positioned relative to adjacent boxes according to the CSS
  <A HREF="#formatting-model">formatting model</A>. Typically, elements like
  'H1' and 'P' are of type 'block'. A value of 'list-item' is similar to 'block'
  except that a list-item marker is added. In HTML, 'LI' will typically have
  this value.
  <P>
  An element with a 'display' value of 'inline' results in a new inline box
  on the same line as the previous content. The box is dimensioned according
  to the formatted size of the content. If the content is text, it may span
  several lines, and there will be a box on each line. The margin, border and
  padding properties apply to 'inline' elements, but will not have any effect
  at the line breaks.
  <P>
  A value of 'none' turns off the display of the element, including children
  elements and the surrounding box.
  <PRE>
  P { display: block }
  EM { display: inline }
  LI { display: list-item }
  IMG { display: none }
</PRE>
  <P>
  The last rule turns off the display of images.
  <P>
  The initial value of 'display' is 'block', but a UA will typically have default
  values for all HTML elements according to the suggested rendering of elements
  in the HTML specification <A HREF="#ref2">[2]</A>.
  <P>
  <EM>CSS1 core:</EM> UAs may ignore 'display' and use only the UA's default
  values. (See <A href="#css1-conformance">section 7</A>.)
  <H4>
    <A NAME="white-space">5.6.2 &nbsp;&nbsp; 'white-space'</A>
  </H4>
  <P>
  <EM>Value:</EM> normal | pre | nowrap<BR>
  <EM>Initial:</EM> normal<BR>
  <EM>Applies to:</EM> block-level elements<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property declares how whitespace inside the element is handled: the
  'normal' way (where whitespace is collapsed), as 'pre' (which behaves like
  the 'PRE' element in HTML) or as 'nowrap' (where wrapping is done only through
  BR elements):
  <PRE>
  PRE { white-space: pre }
  P   { white-space: normal }
</PRE>
  <P>
  The initial value of 'white-space' is 'normal', but a UA will typically have
  default values for all HTML elements according to the suggested rendering
  of elements in the HTML specification <A HREF="#ref2">[2]</A>.
  <P>
  <EM>CSS1 core:</EM> UAs may ignore the 'white-space' property in author's
  and reader's style sheets, and use the UA's default values instead. (See
  <A href="#css1-conformance">section 7</A>.)
  <H4>
    <A NAME="list-style-type">5.6.3 &nbsp;&nbsp; 'list-style-type'</A>
  </H4>
  <P>
  <EM>Value:</EM> disc | circle | square | decimal | lower-roman | upper-roman
  | lower-alpha | upper-alpha | none<BR>
  <EM>Initial:</EM> disc<BR>
  <EM>Applies to:</EM> elements with 'display' value 'list-item'<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property is used to determine the appearance of the list-item marker
  if 'list-style-image' is 'none' or if the image pointed to by the URL cannot
  be displayed.
  <PRE>
  OL { list-style-type: decimal }       /* 1 2 3 4 5 etc. */
  OL { list-style-type: lower-alpha }   /* a b c d e etc. */
  OL { list-style-type: lower-roman }   /* i ii iii iv v etc. */
</PRE>
  <H4>
    <A NAME="list-style-image">5.6.4 &nbsp;&nbsp; 'list-style-image'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;url&gt; | none<BR>
  <EM>Initial:</EM> none<BR>
  <EM>Applies to:</EM> elements with 'display' value 'list-item'<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  This property sets the image that will be used as the list-item marker. When
  the image is available it will replace the marker set with the 'list-style-type'
  marker.
  <PRE>
  UL { list-style-image: url(http://png.com/ellipse.png) }
</PRE>
  <H4>
    <A NAME="list-style-position">5.6.5 &nbsp;&nbsp; 'list-style-position'</A>
  </H4>
  <P>
  <EM>Value:</EM> inside | outside<BR>
  <EM>Initial:</EM> outside<BR>
  <EM>Applies to:</EM> elements with 'display' value 'list-item'<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The value of 'list-style-position' determines how the list-item marker is
  drawn with regard to the content. For a formatting example see
  <A HREF="#list-item-elements">section 4.1.3</A>.
  <H4>
    <A NAME="list-style">5.6.6 &nbsp;&nbsp; 'list-style'</A>
  </H4>
  <P>
  <EM>Value:</EM> &lt;keyword&gt; || &lt;position&gt; || &lt;url&gt;<BR>
  <EM>Initial:</EM> not defined for shorthand properties<BR>
  <EM>Applies to:</EM> elements with 'display' value 'list-item'<BR>
  <EM>Inherited:</EM> yes<BR>
  <EM>Percentage values:</EM> N/A<BR>
  <P>
  The 'list-style' property is a shorthand notation for setting the three
  properties 'list-style-type', 'list-style-image' and 'list-style-position'
  at the same place in the style sheet.
  <PRE>
  UL { list-style: upper-roman inside }
  UL UL { list-style: circle outside }
  LI.square { list-style: square }
</PRE>
  <P>
  Setting 'list-style' directly on 'LI' elements can have unexpected results.
  Consider:
  <PRE>
  &lt;STYLE TYPE="text/css"&gt;
    OL.alpha LI  { list-style: lower-alpha }
    UL LI        { list-style: disc }
  &lt;/STYLE&gt;
  &lt;BODY&gt;
    &lt;OL CLASS=alpha&gt;
      &lt;LI&gt;level 1
      &lt;UL&gt;
         &lt;LI&gt;level 2
      &lt;/UL&gt;
    &lt;/OL&gt;
  &lt;/BODY&gt;
</PRE>
  <P>
  Since the specificity (as defined in the <A HREF="#cascading-order">cascading
  order</A>) is higher for the first rule in the style sheet in the example
  above, it will override the second rule on all 'LI' elements and only
  'lower-alpha' list styles will be used. It is therefore recommended to set
  'list-style' only on the list type elements:
  <PRE>
  OL.alpha  { list-style: lower-alpha }
  UL        { list-style: disc }
</PRE>
  <P>
  In the above example, inheritance will transfer the 'list-style' values from
  'OL' and 'UL' elements to 'LI' elements.
  <P>
  A URL value can be combined with any other value:
  <PRE>
  UL { list-style: url(http://png.com/ellipse.png) disc }
</PRE>
  <P>
  In the example above, the 'disc' will be used when the image is unavailable.
  <H2>
    <A NAME="units">6 &nbsp;&nbsp; Units</A>
  </H2>
  <H3>
    <A NAME="length-units">6.1 &nbsp;&nbsp; Length units</A>
  </H3>
  <P>
  The format of a length value is an optional sign character ('+' or '-', with
  '+' being the default) immediately followed by a number (with or without
  a decimal point) immediately followed by a unit identifier (a two-letter
  abbreviation). After a '0' number, the unit identifier is optional.
  <P>
  Some properties allow negative length units, but this may complicate the
  formatting model and there may be implementation-specific limits. If a negative
  length value cannot be supported, it should be clipped to the nearest value
  that can be supported.
  <P>
  There are two types of length units: relative and absolute. Relative units
  specify a length relative to another length property. Style sheets that use
  relative units will more easily scale from one medium to another (e.g. from
  a computer display to a laser printer). <A HREF="#percentage-units">Percentage
  units</A> (described below) and keyword values (e.g. 'x-large') offer similar
  advantages.
  <P>
  These relative units are supported:
  <PRE>
  H1 { margin: 0.5em }      /* ems, the height of the element's font */
  H1 { margin: 1ex }        /* x-height, ~ the height of the letter 'x' */
  P  { font-size: 12px }    /* pixels, relative to canvas */
</PRE>
  <P>
  The relative units 'em' and 'ex' are relative to the font size of the element
  itself. The only exception to this rule in CSS1 is the 'font-size' property
  where 'em' and 'ex' values refer to the font size of the parent element.
  <P>
  Pixel units, as used in the last rule, are relative to the resolution of
  the canvas, i.e. most often a computer display. If the pixel density of the
  output device is very different from that of a typical computer display,
  the UA should rescale pixel values. The suggested <EM>reference pixel</EM>
  is the visual angle of one pixel on a device with a pixel density of 90dpi
  and a distance from the reader of an arm's length. For a nominal arm's length
  of 28 inches, the visual angle is about 0.0227 degrees.
  <P>
  Child elements inherit the computed value, not the relative value:
  <PRE>
  BODY {
    font-size: 12pt;
    text-indent: 3em;  /* i.e. 36pt */
  }
  H1 { font-size: 15pt }
</PRE>
  <P>
  In the example above, the 'text-indent' value of 'H1' elements will be 36pt,
  not 45pt.
  <P>
  Absolute length units are only useful when the physical properties of the
  output medium are known. These absolute units are supported:
  <PRE>
  H1 { margin: 0.5in }      /* inches, 1in = 2.54cm */
  H2 { line-height: 3cm }   /* centimeters */
  H3 { word-spacing: 4mm }  /* millimeters */
  H4 { font-size: 12pt }    /* points, 1pt = 1/72 in */
  H4 { font-size: 1pc }     /* picas, 1pc = 12pt */
</PRE>
  <P>
  In cases where the specified length cannot be supported, UAs should try to
  approximate. For all CSS1 properties, further computations and inheritance
  should be based on the approximated value.
  <H3>
    <A NAME="percentage-units">6.2 &nbsp;&nbsp; Percentage units</A>
  </H3>
  <P>
  The format of a percentage value is an optional sign character ('+' or '-',
  with '+' being the default) immediately followed by a number (with or without
  a decimal point) immediately followed by '%'.
  <P>
  Percentage values are always relative to another value, for example a length
  unit. Each property that allows percentage units also defines what value
  the percentage value refer to. Most often this is the font size of the element
  itself:
  <PRE>
  P { line-height: 120% }   /* 120% of the element's 'font-size' */
</PRE>
  <P>
  In all inherited CSS1 properties, if the value is specified as a percentage,
  child elements inherit the resultant value, not the percentage value.
  <H3>
    <A NAME="color-units">6.3 &nbsp;&nbsp; Color units</A>
  </H3>
  <P>
  A color is a either a keyword or a numerical RGB specification.
  <P>
  The suggested list of keyword color names is: aqua, black, blue, fuchsia,
  gray, green, lime, maroon, navy, olive, purple, red, silver, teal, white,
  and yellow. These 16 colors are taken from the Windows VGA palette, and their
  RGB values are not defined in this specification.
  <PRE>
  BODY {color: black; background: white }
  H1 { color: maroon }
  H2 { color: olive }
</PRE>
  <P>
  The RGB color model is being used in numerical color specifications. These
  examples all specify the same color:
  <PRE>
  EM { color: #f00 }              /* #rgb */
  EM { color: #ff0000 }           /* #rrggbb */
  EM { color: rgb(255,0,0) }      /* integer range 0 - 255 */
  EM { color: rgb(100%, 0%, 0%) } /* float range 0.0% - 100.0% */
</PRE>
  <P>
  The format of an RGB value in hexadecimal notation is a '#' immediately followed
  by either three or six hexadecimal characters. The three-digit RGB notation
  (#rgb) is converted into six-digit form (#rrggbb) by replicating digits,
  not by adding zeros. For example, #fb0 expands to #ffbb00. This makes sure
  that white (#ffffff) can be specified with the short notation (#fff) and
  removes any dependencies on the color depth of the display.
  <P>
  The format of an RGB value in the functional notation is 'rgb(' followed
  by a comma-separated list of three numerical values (either three integer
  values in the range of 0-255, or three percentage values in the range of
  0.0% to 100.0%) followed by ')'. Whitespace characters are allowed around
  the numerical values.
  <P>
  Values outside the numerical ranges should be clipped. The three rules below
  are therefore equivalent:
  <PRE>
  EM { color: rgb(255,0,0) }       /* integer range 0 - 255 */
  EM { color: rgb(300,0,0) }       /* clipped to 255 */
  EM { color: rgb(110%, 0%, 0%) }  /* clipped to 100% */
</PRE>
  <P>
  RGB colors are specified in the sRGB color space <A HREF="#ref9">[9]</A>.
  UAs may vary in the fidelity with which they represent these colors, but
  use of sRGB provides an unambiguous and objectively measurable definition
  of what the color should be, which can be related to international standards
  <A HREF="#ref10">[10]</A>.
  <P>
  UAs may limit their efforts in displaying colors to performing a gamma-correction
  on them. sRGB specifies a display gamma of 2.2 under specified viewing
  conditions. UAs adjust the colors given in CSS such that, in combination
  with an output device's "natural" display gamma, an effective display gamma
  of 2.2 is produced. <A HREF="#appendix-d">Appendix D</A> gives further details
  of this. Note that only colors specified in CSS are affected; e.g., images
  are expected to carry their own color information.
  <H3>
    <A NAME="url">6.4 &nbsp;&nbsp; URL</A>
  </H3>
  <P>
  A Uniform Resource Locator (URL) is identified with a functional notation:
  <PRE>
  BODY { background: url(http://www.bg.com/pinkish.gif) }
</PRE>
  <P>
  The format of a URL value is 'url(' followed by optional white space followed
  by an optional single quote (') or double quote (") character followed by
  the URL itself (as defined in <A HREF="#ref11">[11]</A>) followed by an optional
  single quote (') or double quote (") character followed by optional whitespace
  followed by ')'. Quote characters that are not part of the URL itself must
  be balanced.
  <P>
  Parentheses, commas, whitespace characters, single quotes (') and double
  quotes (") appearing in a URL must be escaped with a backslash: '\(', '\)',
  '\,'.
  <P>
  Partial URLs are interpreted relative to the source of the style sheet, not
  relative to the document:
  <PRE>
  BODY { background: url(yellow) }
</PRE>
  <H2>
    <A NAME="css1-conformance">7 &nbsp;&nbsp; CSS1 conformance</A>
  </H2>
  <P>
  A User Agent that uses CSS1 to display documents conforms to the CSS1
  specification if it:
  <UL>
    <LI>
      attempts to fetch all referenced style sheets and parse them according to
      this specification
    <LI>
      sorts the declarations according to the cascading order
    <LI>
      implements the CSS1 functionality within the constraints of the presentation
      medium (see explanation below).
  </UL>
  <P>
  A User Agent that outputs CSS1 style sheets conforms to the CSS1 specification
  if it:
  <UL>
    <LI>
      outputs valid CSS1 style sheets
  </UL>
  <P>
  A User Agent that uses CSS1 to display documents <EM>and</EM> outputs CSS1
  style sheets conforms to the CSS1 specification if it meets both sets of
  conformance requirements.
  <P>
  A UA does not have to implement all the functionality of CSS1: it can conform
  to CSS1 by implementing the core functionality. The core functionality consists
  of the whole CSS1 specification except those parts explicitly excluded. In
  the text, those parts are marked with "<EM>CSS1 core:</EM>" followed by an
  explanation of what functionality is outside the core functionality. The
  set of features excluded from the core functionality is called CSS1 advanced
  features.
  <P>
  This section only defines conformance to CSS1. There will be other levels
  of CSS in the future that may require a UA to implement a different set of
  features in order to conform.
  <P>
  Examples of constraints of the presentation medium are: limited resources
  (fonts, color) and limited resolution (so margins may not be accurate). In
  these cases, the UA should approximate the style sheet values. Also, different
  user interface paradigms may have their own constraints: a VR browser may
  rescale the document based on its "distance" from the user.
  <P>
  UAs may offer readers additional choices on presentation. For example, the
  UA may provide options for readers with visual impairments or may provide
  the choice to disable blinking.
  <P>
  Note that CSS1 does not specify all aspects of formatting. E.g., the UA is
  free to select a letter-spacing algorithm.
  <P>
  This specification also recommends, but doesn't require, that a UA:
  <UL>
    <LI>
      allows the reader to specify personal style sheets
    <LI>
      allows individual style sheets to be turned on and off
  </UL>
  <P>
  The above conformance rules describe only functionality, not user interface.
  <H3>
    <A NAME="forward-compatible-parsing">7.1 &nbsp;&nbsp; Forward-compatible
    parsing</A>
  </H3>
  <P>
  This specification defines CSS level 1. It is expected that higher levels
  of CSS, with additional features, will be defined in the future. To ensure
  that UAs supporting just CSS1 will be able to read style sheets containing
  higher level features, this section defines what the UA does when it encounters
  certain constructs that are not valid in CSS level 1.
  <UL>
    <LI>
      a declaration with an unknown property is ignored. For example, if the style
      sheet is
      <PRE>  H1 { color: red; rotation: 70deg }
</PRE>
      <P>
      the UA will treat this as if the style sheet had been
      <PRE>  H1 { color: red; }
</PRE>
    <LI>
      illegal values, <EM>or values with illegal parts</EM>, are treated as if
      the declaration weren't there at all:
      <PRE>
  IMG { float: left }       /* CSS1 */
  IMG { float: left top }   /* "top" is not a value of 'float' */
  IMG { background: "red" } /* keywords cannot be quoted in CSS1 */
  IMG { border-width: 3 }   /* a unit must be specified for length values */
</PRE>
      <P>
      In the above example, a CSS1 parser would honor the first rule and ignore
      the rest, as if the style sheet had been
      <PRE>
  IMG { float: left }
  IMG { }
  IMG { }
  IMG { }
</PRE>
      <P>
      A UA conforming to a future CSS specification may accept one or more of the
      other rules as well.
    <LI>
      an invalid at-keyword is ignored together with everything following it, up
      to and including the next semicolon (;) or brace pair ({...}), whichever
      comes first. For example, assume the style sheet reads:
      <PRE>
  @three-dee {
    @background-lighting {
      azimuth: 30deg;
      elevation: 190deg;
    }
    H1 { color: red }
  }
  H1 {color: blue}
</PRE>
      <P>
      The '@three-dee' is illegal according to CSS1. Therefore, the whole at-rule
      (up to, and including, the third right curly brace) is ignored. The CSS1
      UA skips it, effectively reducing the style sheet to:
      <PRE>
  H1 {color: blue}
</PRE>
  </UL>
  <P>
  In more detail:
  <P>
  A CSS style sheet, for any version of CSS, consists of a list of
  <DFN>statements</DFN>. There are two kinds of statements: <DFN>at-rules</DFN>
  and <DFN>rulesets</DFN>. There may be whitespace (spaces, tabs, newlines)
  around the statements.
  <P>
  CSS style sheets are often embedded in HTML documents, and to be able to
  hide style sheets from older UAs, it is convenient put the style sheets inside
  HTML comments. The HTML comment tokens "&lt;!--" and "--&gt;" may occur before,
  after, and in between the statements. They may have whitespace around them.
  <P>
  At-rules start with an <DFN>at-keyword</DFN>, which is an identifier with
  an '@' at the start (for example: '@import', '@page'). An identifier consists
  of letters, digits, dashes and escaped characters (defined below).
  <P>
  An at-rule consists of everything up to and including the next semicolon
  (;) or the next block (defined shortly), whichever comes first. A CSS1 UA
  that encounters an at-rule that starts with an at-keyword other than '@import'
  ignores the whole of the at-rule and continue parsing after it. It also ignores
  any at-rule that starts with '@import' if it doesn't occur at the top of
  the style sheet, i.e., if it occurs after any rules (even ignored rules).
  Here is an example.
  <P>
  Assume a CSS1 parser encounters this style sheet:
  <PRE>
  @import "subs.css";
  H1 { color: blue }
  @import "list.css";
</PRE>
  <P>
  The second '@import' is illegal according to CSS1. The CSS1 parser skips
  the whole at-rule, effectively reducing the style sheet to:
  <PRE>
  @import "subs.css";
  H1 {color: blue}
</PRE>
  <P>
  A <DFN>block</DFN> starts with a left curly brace ({) and ends with the matching
  right curly brace (}). In between there may be any characters, except that
  parentheses (()), brackets ([]) and braces ({}) always occur in matching
  pairs and may be nested. Single (') and double quotes (") also occur in matching
  pairs, and characters between them are parsed as a <DFN>string</DFN> (see
  the tokenizer in <A HREF="#appendix-b">appendix B</A> for a definition of
  string). Here is an example of a block; note that the right brace between
  the quotes does not match the opening brace of the block, and that the second
  single quote is an escaped character, and thus doesn't match the opening
  quote:
  <PRE>
  { causta: "}" + ({7} * '\'') }
</PRE>
  <P>
  A ruleset consists of a <DFN>selector-string</DFN> followed by a
  <DFN>declaration-block</DFN>. The selector-string consists of everything
  up to (but not including) the first left curly brace ({). A ruleset that
  starts with a selector-string that is not valid CSS1 is skipped.
  <P>
  For example, assume a CSS1 parser encounters this style sheet:
  <PRE>
  H1 { color: blue }
  P[align], UL { color: red; font-size: large }
  P EM { font-weight: bold }
</PRE>
  <P>
  The second line contains a selector-string that is illegal in CSS1. The CSS1
  UA will skip the ruleset, reducing the style sheet to:
  <PRE>
  H1 { color: blue }
  P EM { font-weight: bold }
</PRE>
  <P>
  A declaration-block starts with a left curly brace ({) and ends with the
  matching right curly brace (}). In between there is a list of zero or more
  <DFN>declarations,</DFN> separated by semicolons (;).
  <P>
  A declaration consists of a <DFN>property</DFN>, a colon (:) and a
  <DFN>value</DFN>. Around each of these there may be whitespace. A property
  is an identifier, as defined earlier. Any character may occur in the value,
  but parentheses (()), brackets ([]), braces ({}), single quotes (') and double
  quotes (") must come in matching pairs. Parentheses, brackets, and braces
  may be nested. Inside the quotes, characters are parsed as a string.
  <P>
  To ensure that new properties and new values for existing properties can
  be added in the future, a UA must skip a declaration with an invalid property
  name or an invalid value. Every CSS1 property has its own syntactic and semantic
  restrictions on the values it accepts.
  <P>
  For example, assume a CSS1 parser encounters this style sheet:
  <PRE>
  H1 { color: red; font-style: 12pt }
  P { color: blue;  font-vendor: any;  font-variant: small-caps }
  EM EM { font-style: normal }
</PRE>
  <P>
  The second declaration on the first line has an invalid value '12pt'. The
  second declaration on the second line contains an undefined property
  'font-vendor'. The CSS1 parser will skip these declarations, reducing the
  style sheet to:
  <PRE>
  H1 { color: red; }
  P { color: blue;  font-variant: small-caps }
  EM EM { font-style: normal }
</PRE>
  <P>
  Comments (see <A href="#comments">section 1.7</A>) can occur anywhere where
  whitespace can occur and are considered to be whitespace. CSS1 defines additional
  places where whitespace can occur (such as inside values) and comments are
  allowed there as well.
  <P>
  The following rules always hold:
  <UL>
    <LI>
      All CSS style sheets are case-insensitive, except for parts that are not
      under the control of CSS. I.e., in CSS1, font family names and URLs can be
      case-sensitive. Also, the case-sensitivity of the CLASS and ID attributes
      is under the control of HTML <A HREF="#ref2">[2]</A>.
    <LI>
      in CSS1, selectors (element names, classes and IDs) can contain only the
      characters A-Z, 0-9, and Unicode characters 161-255, plus dash (-); they
      cannot start with a dash or a digit; they can also contain escaped characters
      and any Unicode character as a numeric code (see next item).
    <LI>
      the backslash followed by at most four hexadecimal digits (0..9A..F) stands
      for the Unicode character with that number.
    <LI>
      any character except a hexadecimal digit can be escaped to remove its special
      meaning, by putting a backslash in front, Example: "\"" is a string consisting
      of one double quote.
    <LI>
      the two preceding items define <EM>backslash-escapes</EM>. Backslash-escapes
      are always considered to be part of an identifier, except inside strings
      (i.e., "\7B" is not punctuation, even though "{" is, and "\32" is allowed
      at the start of a class name, even though "2" is not).
  </UL>
  <P>
  Note: The CLASS attribute of HTML allows more characters in a class name
  than the set allowed for selectors above. In CSS1, these characters have
  to be escaped or written as Unicode numbers: "B&amp;W?" can be written as
  "B\&amp;W\?" or "B\26W\3F", "&#186;&#191;&Aring;&Aacute;&#191;&Acirc;" (Greek:
  "kouros") has to be written as "\3BA\3BF\3C5\3C1\3BF\3C2". It is expected
  that in later versions of CSS more characters can be entered directly.
  <P>
  <A HREF="#appendix-b">Appendix B</A> gives a grammar for CSS1.
  <H2>
    <A NAME="references">8 &nbsp;&nbsp; References</A>
  </H2>
  <P>
  <A NAME="ref1">[1]</A> W3C <A HREF="http://www.w3.org/pub/WWW/Style">resource
  page on web style sheets</A> (http://www.w3.org/pub/WWW/Style)
  <P>
  <A NAME="ref2">[2]</A> Sometime in 1997 we expect there to be a single HTML
  specification that has support for Style Sheets and Internationalization.
  Among the works in progess in this area is
  "<A HREF="http://www.w3.org/pub/WWW/TR/WD-style.html">HTML3 and Style
  Sheets</A>" (http://www.w3.org/pub/WWW/TR/WD-style) and the
  "<A HREF="http://www.w3.org/pub/WWW/MarkUp/Cougar/HTML.dtd">Cougar DTD</A>"
  (http://www.w3.org/pub/WWW/MarkUp/Cougar/HTML.dtd).
  <P>
  <A NAME="ref3">[3]</A> T Berners-Lee, D Connolly: "Hypertext Markup Language
  - 2.0", <A href="ftp://ds.internic.net/rfc/rfc1866.txt">RFC 1866</A>, MIT/W3C,
  November 1995. The specification is also available in
  <A HREF="http://www.w3.org/pub/WWW/MarkUp/html-spec/html-spec_toc.html">hypertext
  form</A> (http://www.w3.org/pub/WWW/MarkUp/html-spec/html-spec_toc.html)
  <P>
  <A NAME="ref4">[4]</A> F Yergeau, G Nicol, G Adams, M D&uuml;rst:
  "<A HREF="ftp://ietf.org/internet-drafts/draft-ietf-html-i18n-05.txt">Internationalization
  of the Hypertext Markup Language</A>"
  (ftp://ietf.org/internet-drafts/draft-ietf-html-i18n-05.txt).
  <P>
  <A NAME="ref5">[5]</A> <A HREF="http://www.iso.ch/cate/d16387.html">ISO
  8879:1986</A>. Information Processing - Text and Office Systems - Standard
  Generalized Markup Language (SGML)
  <P>
  <A NAME="ref6">[6]</A> <A HREF="http://www.iso.ch/cate/d18196.html">ISO/IEC
  10179:1996</A> Information technology -- Processing languages -- Document
  Style Semantics and Specification Language (DSSSL). The specification is
  also available in
  <A HREF="http://occam.sjf.novell.com:8080/dsssl/dsssl96">hypertext form
  (http://occam.sjf.novell.com:8080/dsssl/dsssl96).</A>
  <P>
  <A NAME="ref7">[7]</A> <A HREF="http://www.iso.ch/cate/d17782.html">ISO/IEC
  9899:1990</A> Programming languages -- C.
  <P>
  <A NAME="ref8">[8]</A> The Unicode Consortium, "The Unicode Standard -- Worldwide
  Character Encoding -- Version 1.0", Addison-Wesley, Volume 1, 1991, Volume
  2, 1992.
  <P>
  <A NAME="ref9">[9]</A> M Anderson, R Motta, S Chandrasekar, M Stokes:
  "<A HREF="http://www.hpl.hp.com/personal/Michael_Stokes/srgb.htm">Proposal
  for a Standard Color Space for the Internet - sRGB</A>"
  (http://www.hpl.hp.com/personal/Michael_Stokes/srgb.htm)
  <P>
  <A NAME="ref10">[10]</A> CIE Publication 15.2-1986,
  "<A HREF="http://www.hike.te.chiba-u.ac.jp/ikeda/CIE/publ/abst/15-2-86.html">Colorimetry,
  Second Edition</A>", ISBN 3-900-734-00-3
  (http://www.hike.te.chiba-u.ac.jp/ikeda/CIE/publ/abst/15-2-86.html)
  <P>
  <A NAME="ref11">[11]</A> T Berners-Lee, L Masinter, M McCahill: "Uniform
  Resource Locators (URL)", <A href="ftp://ds.internic.net/rfc/rfc1738.txt">RFC
  1738</A>, CERN, Xerox Corporation, University of Minnesota, December 1994
  <P>
  <A NAME="ref11">[12]</A>
  "<A href="http://www.w3.org/pub/WWW/TR/REC-png-multi.html">PNG (Portable
  Network Graphics) Specification, Version 1.0 specification</A>"
  (http://www.w3.org/pub/WWW/TR/REC-png-multi.html)
  <P>
  <A NAME="ref12">[13]</A> Charles A. Poynton:
  "<A HREF="ftp://ftp.inforamp.net/pub/users/poynton/doc/Mac/Mac_gamma.pdf">Gamma
  correction on the Macintosh Platform</A>"
  (ftp://ftp.inforamp.net/pub/users/poynton/doc/Mac/Mac_gamma.pdf)
  <P>
  <A NAME="ref13">[14]</A> International Color Consortium:
  "<A HREF="ftp://sgigate.sgi.com/pub/icc/ICC32.pdf">ICC Profile Format
  Specification, version 3.2</A>", 1995 (ftp://sgigate.sgi.com/pub/icc/ICC32.pdf)
  <P>
  <A NAME="ref15">[15]</A> S C Johnson: "YACC - Yet another compiler compiler",
  Technical Report, Murray Hill, 1975
  <P>
  <A NAME="ref16">[16]</A> "Flex: The Lexical Scanner Generator", Version 2.3.7,
  ISBN 1882114213
  <H2>
    <A NAME="acknowledgments">9 &nbsp;&nbsp; Acknowledgments</A>
  </H2>
  <P>
  During the short life of HTML, there have been several
  <A HREF = "http://www.w3.org/hypertext/WWW/Style/">style sheet proposals</A>
  to which this proposal is indebted. Especially the proposals from Robert
  Raisch, Joe English and Pei Wei were influential.
  <P>
  A number of people have contributed to the development of CSS1. We would
  especially like to thank: Terry Allen, Murray Altheim, Glenn Adams, Walter
  Bender, Tim Berners-Lee, Yves Bertot, Scott Bigham, Steve Byrne, Robert Cailliau,
  James Clark, Daniel Connolly, Donna Converse, Adam Costello, Todd Fahrner,
  Todd Freter, Roy Fielding, Neil Galarneau, Wayne Gramlich, Phill Hallam-Baker,
  Philipp Hoschka, Kevin Hughes, Scott Isaacs, Tony Jebson, William Johnston,
  Gilles Kahn, Philippe Kaplan, Phil Karlton, Evan Kirshenbaum, Yves Lafon,
  Murray Maloney, Lou Montulli, Colas Nahaboo, Henrik Frystyk Nielsen, David
  Perrell, William Perry, Scott Preece, Paul Prescod, Liam Quin, Vincent Quint,
  Jenny Raggett, Thomas Reardon, C&eacute;cile Roisin, Michael Seaton, David
  Seibert, David Siegel, David Singer, Benjamin Sittler, Jon Smirl, Charles
  Peyton Taylor, Ir&egrave;ne Vatton, Daniel Veillard, Mandira Virmani, Greg
  Watkins, Mike Wexler, Lydja Williams, Brian Wilson, Chris Wilson, Lauren
  Wood and Stephen Zilles.
  <P>
  Three people deserve special mentioning: Dave Raggett (for his encouragement
  and work on HTML3), Chris Lilley (for his continued contributions, especially
  in the area of colors and fonts) and Steven Pemberton (for his organizational
  as well as creative skills).
  <H2>
    <A NAME="appendix-a">Appendix A: Sample style sheet for HTML 2.0</A>
  </H2>
  <P>
  (This appendix is informative, not normative)
  <P>
  The following style sheet is written according to the suggested rendering
  in the HTML 2.0 <A HREF="#ref3">[3]</A> specification. Some styles, e.g.
  colors, have been added for completeness. It is suggested that a style sheet
  similar to the one below is used as the UA default.
  <PRE>
  BODY { 
    margin: 1em;
    font-family: serif;
    line-height: 1.1;
    background: white;
    color: black; 
  }

  H1, H2, H3, H4, H5, H6, P, UL, OL, DIR, MENU, DIV, 
  DT, DD, ADDRESS, BLOCKQUOTE, PRE, BR, HR { display: block }

  B, STRONG, I, EM, CITE, VAR, TT, CODE, KBD, SAMP, 
  IMG, SPAN { display: inline }

  LI { display: list-item }

  H1, H2, H3, H4 { margin-top: 1em; margin-bottom: 1em }
  H5, H6 { margin-top: 1em }
  H1 { text-align: center }
  H1, H2, H4, H6 { font-weight: bold }
  H3, H5 { font-style: italic }

  H1 { font-size: xx-large }
  H2 { font-size: x-large }
  H3 { font-size: large }

  B, STRONG { font-weight: bolder }  /* relative to the parent */
  I, CITE, EM, VAR, ADDRESS, BLOCKQUOTE { font-style: italic }
  PRE, TT, CODE, KBD, SAMP { font-family: monospace }

  PRE { white-space: pre }

  ADDRESS { margin-left: 3em }
  BLOCKQUOTE { margin-left: 3em; margin-right: 3em }

  UL, DIR { list-style: disc }
  OL { list-style: decimal }
  MENU { margin: 0 }              /* tight formatting */
  LI { margin-left: 3em }

  DT { margin-bottom: 0 }
  DD { margin-top: 0; margin-left: 3em }

  HR { border-top: solid }        /* 'border-bottom' could also have been used */

  A:link { color: blue }          /* unvisited link */
  A:visited { color: red }        /* visited links */
  A:active { color: lime }        /* active links */

  /* setting the anchor border around IMG elements
     requires contextual selectors */

  A:link IMG { border: 2px solid blue }
  A:visited IMG { border: 2px solid red }
  A:active IMG { border: 2px solid lime }
</PRE>
  <H2>
    <A NAME="appendix-b">Appendix B: CSS1 grammar</A>
  </H2>
  <P>
  (This appendix is normative)
  <P>
  The minimal CSS (i.e., any version of CSS) grammar that all implementations
  need to support is defined in <A HREF="#forward-grammar">section 7</A>. The
  grammar below defines a much smaller language, a language that defines the
  syntax of CSS1.
  <P>
  It is in some sense, however, still a superset of CSS1: there are additional
  semantic constraints not expressed in this grammar. A conforming UA must
  also adhere to the forward-compatible parsing rules (section 7.1), the property
  and value notation (section 5) and the unit notation (section 6). In addition,
  HTML imposes restrictions, e.g., on the possible values of the CLASS attribute.
  <P>
  The grammar below is LL(1) (but note that most UA's should not use it directly,
  since it doesn't express the parsing conventions, only the CSS1 syntax).
  The format of the productions is optimized for human consumption and some
  shorthand notation beyond yacc <A HREF="#ref15">[15]</A> is used:
  <PRE>  *  : 0 or more
  +  : 1 or more
  ?  : 0 or 1
  |  : separates alternatives
  [] : grouping 
</PRE>
  <P>
  The productions are:
  <PRE>
stylesheet
 : [CDO|CDC]* [ import [CDO|CDC]* ]* [ ruleset [CDO|CDC]* ]*
 ;
import
 : IMPORT_SYM [STRING|URL] ';'		/* E.g., @import url(fun.css); */
 ;
unary_operator
 : '-' | '+'
 ;
operator
 : '/' | ',' | /* empty */
 ;
property
 : IDENT
 ;
ruleset
 : selector [ ',' selector ]*
   '{' declaration [ ';' declaration ]* '}'
 ;
selector
 : simple_selector+ [ pseudo_element | solitary_pseudo_element ]?
 | solitary_pseudo_element
 ;
	/* An "id" is an ID that is attached to an element type
	** on its left, as in: P#p007
	** A "solitary_id" is an ID that is not so attached,
	** as in: #p007
	** Analogously for classes and pseudo-classes.
	*/
simple_selector
 : element_name id? class? pseudo_class?	/* eg: H1.subject */
 | solitary_id class? pseudo_class?		/* eg: #xyz33 */
 | solitary_class pseudo_class?			/* eg: .author */
 | solitary_pseudo_class			/* eg: :link */
 ;
element_name
 : IDENT
 ;
pseudo_class					/* as in:  A:link */
 : LINK_PSCLASS_AFTER_IDENT
 | VISITED_PSCLASS_AFTER_IDENT
 | ACTIVE_PSCLASS_AFTER_IDENT
 ;
solitary_pseudo_class				/* as in:  :link */
 : LINK_PSCLASS
 | VISITED_PSCLASS
 | ACTIVE_PSCLASS
 ;
class						/* as in:  P.note */
 : CLASS_AFTER_IDENT
 ;
solitary_class					/* as in:  .note */
 : CLASS
 ;
pseudo_element					/* as in:  P:first-line */
 : FIRST_LETTER_AFTER_IDENT
 | FIRST_LINE_AFTER_IDENT
 ;
solitary_pseudo_element				/* as in:  :first-line */
 : FIRST_LETTER
 | FIRST_LINE
 ;
	/* There is a constraint on the id and solitary_id that the
	** part after the "#" must be a valid HTML ID value;
	** e.g., "#x77" is OK, but "#77" is not.
	*/
id
 : HASH_AFTER_IDENT
 ;
solitary_id
 : HASH
 ;
declaration
 : property ':' expr prio? 
 | /* empty */				/* Prevents syntax errors... */
 ;
prio
 : IMPORTANT_SYM	 		/* !important */
 ;
expr
 : term [ operator term ]*
 ;
term
 : unary_operator?
   [ NUMBER | STRING | PERCENTAGE | LENGTH | EMS | EXS
   | IDENT | hexcolor | URL | RGB ]
 ;
	/* There is a constraint on the color that it must
	** have either 3 or 6 hex-digits (i.e., [0-9a-fA-F])
	** after the "#"; e.g., "#000" is OK, but "#abcd" is not.
	*/
hexcolor
 : HASH | HASH_AFTER_IDENT
 ;
</PRE>
  <P>
  The following is the tokenizer, written in flex <A HREF="#ref16">[16]</A>
  notation. Note that this assumes an 8-bit implementation of flex. The tokenizer
  is case-insensitive (flex command line option -i).
  <PRE>
unicode		\\[0-9a-f]{1,4}
latin1		[&#161;-&yuml;]
escape		{unicode}|\\[ -~&#161;-&yuml;]
stringchar	{escape}|{latin1}|[ !#$%&amp;(-~]
nmstrt		[a-z]|{latin1}|{escape}
nmchar		[-a-z0-9]|{latin1}|{escape}
ident		{nmstrt}{nmchar}*
name		{nmchar}+
d		[0-9]
notnm		[^-a-z0-9\\]|{latin1}
w		[ \t\n]*
num		{d}+|{d}*\.{d}+
string		\"({stringchar}|\')*\"|\'({stringchar}|\")*\'

%x COMMENT
%s AFTER_IDENT

%%
"/*"				{BEGIN(COMMENT);}
&lt;COMMENT&gt;"*/"			{BEGIN(0);}
&lt;COMMENT&gt;\n			{/* ignore */}
&lt;COMMENT&gt;.			{/* ignore */}
@import				{BEGIN(0); return IMPORT_SYM;}
"!"{w}important			{BEGIN(0); return IMPORTANT_SYM;}
{ident}				{BEGIN(AFTER_IDENT); return IDENT;}
{string}			{BEGIN(0); return STRING;}

{num}				{BEGIN(0); return NUMBER;}
{num}"%"			{BEGIN(0); return PERCENTAGE;}
{num}pt/{notnm}			{BEGIN(0); return LENGTH;}
{num}mm/{notnm}			{BEGIN(0); return LENGTH;}
{num}cm/{notnm}			{BEGIN(0); return LENGTH;}
{num}pc/{notnm}			{BEGIN(0); return LENGTH;}
{num}in/{notnm}			{BEGIN(0); return LENGTH;}
{num}px/{notnm}			{BEGIN(0); return LENGTH;}
{num}em/{notnm}			{BEGIN(0); return EMS;}
{num}ex/{notnm}			{BEGIN(0); return EXS;}

&lt;AFTER_IDENT&gt;":"link		{return LINK_PSCLASS_AFTER_IDENT;}
&lt;AFTER_IDENT&gt;":"visited	{return VISITED_PSCLASS_AFTER_IDENT;}
&lt;AFTER_IDENT&gt;":"active	{return ACTIVE_PSCLASS_AFTER_IDENT;}
&lt;AFTER_IDENT&gt;":"first-line	{return FIRST_LINE_AFTER_IDENT;}
&lt;AFTER_IDENT&gt;":"first-letter	{return FIRST_LETTER_AFTER_IDENT;}
&lt;AFTER_IDENT&gt;"#"{name}		{return HASH_AFTER_IDENT;}
&lt;AFTER_IDENT&gt;"."{name}		{return CLASS_AFTER_IDENT;}

":"link				{BEGIN(AFTER_IDENT); return LINK_PSCLASS;}
":"visited			{BEGIN(AFTER_IDENT); return VISITED_PSCLASS;}
":"active			{BEGIN(AFTER_IDENT); return ACTIVE_PSCLASS;}
":"first-line			{BEGIN(AFTER_IDENT); return FIRST_LINE;}
":"first-letter			{BEGIN(AFTER_IDENT); return FIRST_LETTER;}
"#"{name}			{BEGIN(AFTER_IDENT); return HASH;}
"."{name}			{BEGIN(AFTER_IDENT); return CLASS;}

url\({w}{string}{w}\)					|
url\({w}([^ \n\'\")]|\\\ |\\\'|\\\"|\\\))+{w}\)		{BEGIN(0); return URL;}
rgb\({w}{num}%?{w}\,{w}{num}%?{w}\,{w}{num}%?{w}\)	{BEGIN(0); return RGB;}

[-/+{};,#:]			{BEGIN(0); return *yytext;}
[ \t]+				{BEGIN(0); /* ignore whitespace */}
\n				{BEGIN(0); /* ignore whitespace */}
\&lt;\!\-\-			{BEGIN(0); return CDO;}
\-\-\&gt;				{BEGIN(0); return CDC;}
.				{fprintf(stderr, "%d: Illegal character (%d)\n",
				 lineno, *yytext);}
</PRE>
  <H2>
    <A NAME="appendix-c">Appendix C: Encoding</A>
  </H2>
  <P>
  (This appendix is informative, not normative)
  <P>
  HTML documents may contain any of the about 30,000 different characters defined
  by Unicode. Many documents only need a few hundred. Many fonts also only
  contain just a few hundred glyphs. In combination with
  <A HREF="#font-properties">section 5.2</A>, this appendix explains how the
  characters in the document and the glyphs in a font are matched.
  <H3>
    <A name="character-encoding">Character encoding</A>
  </H3>
  <P>
  The content of an HTML document is a sequence of <EM>characters</EM> and
  markup. To send it "over the wire", it is encoded as a sequence of bytes,
  using one of several possible <EM>encodings</EM>. The HTML document has to
  be decoded to find the characters. For example, in Western Europe it is customary
  to use the byte 224 for an a-with-grave-accent (&agrave;), but in Hebrew,
  it is more common to use 224 for an Aleph. In Japanese, the meaning of a
  byte usually depends on the bytes that preceded it. In some encodings, one
  character is encoded as two (or more) bytes.
  <P>
  The UA knows how to decode the bytes by looking at the "charset" parameter
  in the HTTP header. Typical encodings (charset values) are "ASCII" (for English),
  "ISO-8859-1" (for Western Europe), "ISO-8859-8" (for Hebrew), "Shift-JIS"
  (for Japanese).
  <P>
  HTML <A HREF="#ref2">[2]</A><A HREF="#ref4">[4]</A>, allows some 30,000 different
  characters, namely those defined by Unicode. Not many documents will use
  that many different characters, and choosing the right encoding will usually
  ensure that the document only needs one byte per character. Occasional characters
  outside the encoded range can still be entered as numerical character references:
  '&amp;#928;' will always mean the Greek uppercase Pi, no matter what encoding
  was used. Note that this entails that UAs have to be prepared for any Unicode
  character, even if they only handle a few encodings.
  <H3>
    <A name="font-encoding">Font encoding</A>
  </H3>
  <P>
  A font doesn't contain <EM>characters</EM>, it contains pictures of characters,
  known as <EM>glyphs</EM>. The glyphs, in the form of outlines or bitmaps,
  constitute a particular representation of a character. Either explicitly
  or implicitly, each font has a table associated with it, the <EM>font encoding
  table</EM>, that tells for each glyph what character it is a representation
  for. In Type 1 fonts, the table is referred to as an <EM>encoding vector</EM>.
  <P>
  In fact, many fonts contain several glyphs for the same character. Which
  of those glyphs should be used depends either on the rules of the language,
  or on the preference of the designer.
  <P>
  In Arabic, for example, all letters have four different shapes, depending
  on whether the letter is used at the start of a word, in the middle, at the
  end, or in isolation. It is the same character in all cases, and thus there
  is only one character in the HTML document, but when printed, it looks
  differently each time.
  <P>
  There are also fonts that leave it to the graphic designer to choose from
  among various alternative shapes provided. Unfortunately, CSS1 doesn't yet
  provide the means to select those alternatives. Currently, it is always the
  default shape that is chosen from such fonts.
  <H3>
    <A name="font-sets">Font sets</A>
  </H3>
  <P>
  To deal with the problem that a single font may not be enough to display
  all the characters in a document, or even a single element, CSS1 allows the
  use of <EM>font sets</EM>.
  <P>
  A font set in CSS1 is a list of fonts, all of the same style and size, that
  are tried in sequence to see if they contain a glyph for a certain character.
  An element that contains English text mixed with mathematical symbols may
  need a font set of two fonts, one containing letters and digits, the other
  containing mathematical symbols. See <A href="#font-properties">section 5.2</A>
  for a detailed description of the selection mechanism for font sets.
  <P>
  Here is an example of a font set suitable for a text that is expected to
  contain text with Latin characters, Japanese characters, and mathematical
  symbols:
  <PRE>
  BODY { font-family: Baskerville, Mincho, Symbol, serif }
</PRE>
  <P>
  The characters available in the Baskerville font (a font with only Latin
  characters) will be taken from that font, Japanese will be taken from Mincho,
  and the mathematical symbols will come from Symbol. Any other characters
  will (hopefully) come from the generic font family 'serif'. The 'serif' font
  family will also be used if one or more of the other fonts is unavailable.
  <H2>
    <A NAME="appendix-d">Appendix D: Gamma correction</A>
  </H2>
  <P>
  (This appendix is informative, not normative)
  <P>
  See the <A href="http://www.w3.org/pub/WWW/TR/PNG-GammaAppendix">Gamma
  Tutorial</A> in the PNG specification <A href="#ref12">[12]</A> if you aren't
  already familiar with gamma issues.
  <P>
  In the computation, UAs displaying on a CRT may assume an ideal CRT and ignore
  any effects on apparent gamma caused by dithering. That means the minimal
  handling they need to do on current platforms is:
  <DL>
    <DT>
      PC using MS-Windows
    <DD>
      none
    <DT>
      Unix using X11
    <DD>
      none
    <DT>
      Mac using QuickDraw
    <DD>
      apply gamma 1.39 <A HREF="#ref13">[13]</A> (ColorSync-savvy applications
      may simply pass the sRGB ICC profile <A HREF="#ref14">[14]</A> to ColorSync
      to perform correct color correction)
    <DT>
      SGI using X
    <DD>
      apply the gamma value from <TT>/etc/config/system.glGammaVal</TT> (the default
      value being 1.70; applications running on Irix 6.2 or above may simply pass
      the sRGB ICC profile to the color management system)
    <DT>
      NeXT using NeXTStep
    <DD>
      apply gamma 2.22
  </DL>
  <P>
  "Applying gamma" means that each of the three R, G and B must be converted
  to R'=R<SUP>gamma</SUP>, G'=G<SUP>gamma</SUP>, G'=B<SUP>gamma</SUP>, before
  handing to the OS.
  <P>
  This may rapidly be done by building a 256-element lookup table once per
  browser invocation thus:
  <PRE>
  for i := 0 to 255 do
    raw := i / 255;
    corr := pow (raw, gamma);
    table[i] := trunc (0.5 + corr * 255.0)
  end
</PRE>
  <P>
  which then avoids any need to do transcendental math per color attribute,
  far less per pixel.
  <H2>
    <A NAME="appendix-e">Appendix E: The applicability and extensibility of
    CSS1</A>
  </H2>
  <P>
  (This appendix is informative, not normative)
  <P>
  The goal of the work on CSS1 has been to create a simple style sheet mechanism
  for HTML documents. The current specification is a balance between the simplicity
  needed to realize style sheets on the web, and pressure from authors for
  richer visual control. CSS1 offers:
  <UL>
    <LI>
      visual markup replacement: HTML extensions, e.g. "CENTER", "FONT" and "SPACER",
      are easily replaced with CSS1 style sheets.
    <LI>
      nicer markup: instead of using "FONT" elements to achieve the popular small-caps
      style, one declaration in the style sheet is sufficient. Compare the visual
      markup:
      <PRE>
  &lt;H1&gt;H&lt;FONT SIZE=-1&gt;EADLINE&lt;/FONT&gt;&lt;/H1&gt;
</PRE>
      <P>
      with the style sheet:
      <PRE>
  H1 { font-style: small-caps }

  &lt;H1&gt;Headline&lt;/H1&gt;
</PRE>
    <LI>
      various integration levels: CSS1 style rules can be fetched from external
      style sheets, included in the 'STYLE' element, or put into 'STYLE' attributes.
      The latter option offers easy transition from HTML extensions.
    <LI>
      new effects: some new visual effects have been added to offer users new toys.
      The typographical pseudo-elements and the extra values on the background
      property fall into this category.
    <LI>
      scalability: CSS1 will be useful on equipment ranging from text terminals
      to high-resolution color workstations. Authors can write one style sheet
      and be reasonably sure that the intended style will come across in the best
      possible manner.
  </UL>
  <P>
  CSS1 does not offer:
  <UL>
    <LI>
      per pixel control: CSS1 values simplicity over level of control, and although
      the combination of background images and styled HTML is powerful, control
      to the pixel level is not possible.
    <LI>
      author control: the author cannot enforce the use of a certain sheet, only
      suggest
    <LI>
      a layout language: CSS1 does not offer multiple columns with text-flow,
      overlapping frames etc.
    <LI>
      a rich query language on the parse tree: CSS1 can only look for ancestor
      elements in the parse tree, while other style sheet languages (e.g. DSSSL
      <A HREF="#ref6">[6]</A>) offers a full query language.
  </UL>
  <P>
  We expect to see extensions of CSS in several directions:
  <UL>
    <LI>
      paper: better support for printing HTML documents
    <LI>
      support for non-visual media: work is in the process to add a list of properties
      and corresponding values to support speech and braille output
    <LI>
      color names: the currently supported list may be extended
    <LI>
      fonts: more precise font specification systems are expected to complement
      existing CSS1 font properties.
    <LI>
      values, properties: we expect vendors to propose extensions to the CSS1 set
      of values and properties. Extending in this direction is trivial for the
      specification, but interoperability between different UAs is a concern
    <LI>
      layout language: support for two-dimensional layout in the tradition of desktop
      publishing packages.
    <LI>
      other DTDs: CSS1 has some HTML-specific parts (e.g. the special status of
      the 'CLASS' and 'ID' attributes) but should easily be extended to apply to
      other DTDs as well.
  </UL>
  <P>
  We do not expect CSS to evolve into:
  <UL>
    <LI>
      a programming language
  </UL>
</DIV>
<P>
<A href="http://www.w3.org/Consortium/Legal/ipr-notice.html#Copyright">
Copyright</A> &nbsp;&copy;&nbsp; 1996 <A href="http://www.w3.org">W3C</A>
(<A href="http://www.lcs.mit.edu">MIT</A>,
<A href="http://www.inria.fr/">INRIA</A>,
<A href="http://www.keio.ac.jp/">Keio</A> ), All Rights Reserved. W3C
<A href="http://www.w3.org/Consortium/Legal/ipr-notice.html#Legal Disclaimer">liability,</A>
<A href="http://www.w3.org/Consortium/Legal/ipr-notice.html#W3C Trademarks">trademark</A>,
<A href="http://www.w3.org/Consortium/Legal/copyright-documents.html">document
use </A>and
<A href="http://www.w3.org/Consortium/Legal/copyright-software.html">software
licensing </A>rules apply.
</BODY></HTML>
